COLLEGE OF NURSING

Standard CurriculumDiploma in Post Basic Specialization in Nursing

Title 1202 Physics For Nurses

Hours 30 Hours Theory ; 30 Laboratory

Credits 3 Credits

Course description

This course is designed to provide the Post RN students with educational experiments in

basic physics requires for the better understanding of the principles of nursing , selected

topics essentials for nursing will be included . A small laboratory component is included

to provide opportunities for practical hands on science work and to emphasis the

interdependency of nursing with pure science.

CORSE OBJECTIVES: At the end of this course the students will be able to:

Explain the concepts and principles of physics essential for the practice of nursing

Demonstrate the knowledge of scientific process skills, such as observing,

inferring, classifying, measuring, communication and predicting.

Show an appreciation of role played by science in the understanding natural

phenomenon and their role in nursing.

TEACHING / LEARNING STRATEGIES:

Lectures, discussion, tutorials, group discussions, assignments and self study

COURSE EXPECTATIONS

Attendance in class 85%

Satisfactory completion of the work

Completion of the assignments and tests on dates due

Evaluation criteria

Laboratory 20%

Midterm examination 30%

Final examination 50%

COURSE CONTENTS

UNIT I INTRODUCTION TO PHYSICS Definition of physics Importance of physics

UNIT II MEASUREMENT measurement and its importance Concepts of fundamental and derived units British system and its three fundamental  units S.I system and its Seven fundamental  units Prefixes Advantages of S.I units Inert-conversion of S.I. Units

UNIT III DEFINITION OF MOTION AND REST Types of motion ,i.e. curvilinear and rectilinear Definitions of units of speed and velocity Newton’s laws of motion Definitions of force ,acceleration, acceleration due to gravity and their units Friction and its types Advantages and disadvantages of friction Measures to decrease friction Application of friction in nursing and daily life

UNIT IV GRAVITY AND STABILITY Newton’s laws of gravity Definition of centre of gravity Determination of CG of regular and irregular objects Application of gravity in nursing and daily life Definition of stability and equilibrium Definition of moment and torque Laws of moment and its application

UNIT V WORK ,POWER AND ENERGY Energy and its different kinds Kinetic energy and potential energy Energy, work and power and their S. I Units Machines and their functions Six simple machines : liver pulley ,screw, wheel and axle , inclined plane

and wedge Definition of efficiency ,input, output ,effort, resistance and mechanical

advantage Clinical implications of machines, traction and lifting etc.

UNIT VI HEAT Definition of heat and its S.I Units Definition of temperature Difference between heat and temperature Measures of temperature in terms of Celsius and Fahrenheit Scales and their

inter-conversion Change of state of solids, liquids and gases and their applications Transfer of heat i.e. conduction, convection and radiation and its

applications

UNIT VII

PRESUURE Definition of pressure and its S.I Units Importance of pressure in nursing Pressure in hydrostatic fluids Pascal’s law and its application Atmospheric pressure and its application Measurement of atmospheric pressure Negative and positive pressure Gas laws and their applications

o Boyles, law o Charles law o Gay Lussac law

UNIT VIII

SOUND AND LIGHT Wave nature of sound and light Selected properties of light Selected properties of sound Ultrasound

UNIT IX

ELECTRICITY Nature of electricity Units of electrical measurement such as ampere and volt Precautions in the use of electricity in the hospital setting

PHYSICS Laboratory:• Measurements: How to measure the length, mass volume of simple everyday objects in

S.I Units.

• Pressure

REFERENCES:

Flitter , H.H (1989).Physics in Nursing. St. Louis: C.V Mosby

Lankford, T.R (1984). Integrated Sciences for Health Students. Virginia: Reston Co.

Hinword .B (1993). A Text book of Science for the Health Professionals .

London:Chapman and Mall.

UNIT NO. 1PHYSICS

It is the branch of science, which deals with the study of properties of matter, energy and their mutual relationship.There are two main divisions of physics which are:

a. Classical physics: motion and energy, mechanics, force and motion, heat, sound, electricity, magnetism and light.

b. Modern physics: atomic, molecular and electron physics, nuclear physics, relativity, origin of universe, astrophysics.

Following are the branches of Physics:Mechanics: -It is the study of motion and the physical affect which influence motion.Heat & Thermodynamics: -It is the study of thermal energy possessed by molecules.Sound: -It is the study of physical aspects of audible sound energy.Light: -It is the study of physical aspects of visible light.Electromagnetism: -It is the study of electromagnetism phenomena and mutual relationship between them.Atomic and molecular physics: -It is the study of atoms and molecules of material things.Nuclear Physics: -It is study of isolated nuclei of the atoms.Plasma Physics: -Matter becomes gas on very high temperature. This is called plasma. The study of properties of matter is this state is called plasma physics.Solid State Physics: -It is the study of properties of matter in solid form is called solid state physics. It has three branchesi) Astrophysics is the study of heavenly bodies.ii) Geophysics is the study of internal structure of earth.iii) Biophysics is the study of biological sciences on the basis of physics.Study of Physics As the other branches of science, scientific skills are necessary in the process of undertaking research and analysis in physics.Research or Experiments are done systematically and step by step based on scientific method.Scientific methodIdentifying Problem ---- Making Hypothesis -----Planning investigation ------Identifying and controlling variables ----conducting experiment ----collecting data ----recording data----making conclusions---writing reports.Careers in Physics (examples)1. Engineering2. Computer Science3. Industry4. Communication5. Electronics6. Medicine – X ray7. Environmental Science8. Basic Research

IMPORTANCE OF PHYSICS IN NURSING

The study of physics enables the nurses

To understand the relationship of different properties of matter and energy. To understand the basic fundamental units of measurement, necessary for the

accuracy of fluids and medicines during nursing practice. It helps to understand the mechanism of friction and its effects on patients.

The nurses: Will be able to understand the measures to decrease friction. Will be able to understand the use of different machines in daily life and patient care. Will be able to understand the gravity and it effects on different positions of patients

during procedures. Will be able to understand the Gas laws and their effects in respiration Will be able to understand the nature of electricity and its uses and precautions

during procedures. It helps to understand the nature of waves and sound and their frequency and uses

in daily life.

UNIT NO. 02

MEASUREMENT Why do we need a standardized system of measurement?

Scientific community is global.An international “language” of measurement allows a scientist to share, interpret,

and compare experimental findings with other scientists, regardless of nationality or language barriers.

There are several systems of units, each containing units for properties such as length, volume, weight, and time.By the 1700s, every country used its own system of weights and measures. Only the England had three different systems just within its own borders.

The English /British System of UnitsIn the English system the units are defined in an arbitrary way.

Length Area12 inches = 1 foot 144 square inches = 1 square foot3 feet = 1 yard 9 square feet = 1 square yard220 yards = 1 furlong 4,840 square yards = 1 acre 8 furlongs = 1 mile 640 acres = 1 square mile5,280 feet = 1 mile 1 square mile = 1 section 1,760 yards = 1 mile 36 sections = 1 township Volume   Capacity (Dry)  1,728 cubic inches

= 1 cubic foot16 fluid ounces/2 cup

= 1 pint

27 cubic feet = 1 cubic yard 2 pints /32 ounces = 1 quart Mass   8 quarts = 1 peck 437.5 grains = 1 ounce 4 pecks = 1 bushel 16 ounces = 1 pound Capacity (Liquid)  14 pounds = 1 stone 4 gills = 1 pint

100 pounds= 1 hundred weight

2 pints = 1 quart

20 hundred weights

= 1 ton 4 quarts = 1 gallon

Apothecaries' Measures  Troy Weights  60 minims = 1 fluid dram 24 grains = 1 pennyweight8 fluid drams = 1 fluid ounce 20 pennyweights = 1 ounce16 fluid ounces = 1 pintApothecaries' Weights 20 grains = 1 scruple 16 ounces = I lb3 scruples = 1 dram 2000 lb = 1 ton8 drams = 1 ounceTime: second (s), minute (min), hour (h), day (d), year (y)60 s = 1 min 24 h = 1 d 60 min = 1 h 3651/4 d = 1 y

Metric System & SI

The SI stands for "System International”.  There are 3 fundamental SI units for LENGTH, MASS, and TIME. 

• The first standardized system of measurement: the “Metric” systemo Developed in France in 1791o Named based on French word for “measure”o based on the decimal (powers of 10)

• System International de,Unites (International System of Units)o Modernized version of the Metric Systemo Abbreviated by the letters SI.o Established in 1960, at the 11th General Conference on Weights and

Measures.o Units, definitions, and symbols were revised and simplified.

• Components of the SI System• The SI system of measurement has 3 parts:

o base unitso derived unitso prefixes

• Unit: measure of the quantity that is defined to be exactly 1• Prefix: modifier that allows us to express multiples or fractions of a base unit• As we progress through the course, we will introduce different base units and

derived units.

National Bureau of StandardsInternational Bureau of Weight and Measures in Paris

Physical quantity: A quantity that can be measured by instrument, clearly defined and has proper units is called physical quantity. Physical quantities are classified as fundamental and derived quantitiesFundamental units The physical quantity which does not depend on any other physical quantity is called a fundamental physical quantity such as length; mass and time are called fundamental unitsSystem of units: There are three systems of units.

Name of system

Fundamental unit ofLength Mass Time

F.P.S. Foot Pound SecondC.G.S. Centimetre Gram SecondM.K.S. (S.I.) Meter Kilogram Second

The base units:A unit of measurement that can be determined by taking one measurement

without having to combine with any other measurement Length, mass, and temperature are examples of base units.

The Seven Base SI UnitsQuantity

Unit Symbol

Length meter mMass kilogram kgTemperature Kelvin KTime second sAmount of Substance mole molLuminous Intensity candela cdElectric current ampere A

DEFINITIONS OF FUNDAMENTAL UNITS(i) Meter:   Meter is defined as "The distance between the two marks on a Platinum-

Iridium bar kept at 0OC in the   International Bureau of Weight and Measures in Paris." The currently accepted definition of meter is the length of path travelled by

light in vacuum in 1/299,792,458th second.(ii) Kilogram: Kilogram is the fundamental unit of mass. It is defined as the mass of a

specific cylinder of platinum - iridium kept at the International Bureau of Weights and Measures in Paris.

(iii) Second: Second is the fundamental unit of time. It is defined as 86,400th part of a mean solar day. Second is accurately measured by an atomic clock.   A second is defined in terms of the time period of Cs-133 atoms.  i.e." one second is equal to 9,192,631,770 periods of vibrations of Cs-133 atoms."  60 seconds = one minute  3600 seconds = one hour

(iv) Coulomb: Coulomb is the fundamental unit of charge. It is defined as the charge required to obtain 9´109 newton of force between two equal charges separated at a distance of one meter in vacuum.

(v) Candela: Candela is the fundamental unit of luminous intensity. It is defined as luminous intensity observed from a source of monochromatic light of frequency 540x1012 Hz, that has an intensity of 1/683 watt per steradian.

(vi) Kelvin: Kelvin is the fundamental unit of temperature. It has value of zero where the molecular activity of gases cease.

(vii) Mole: Mole is the fundamental unit of quantity of matter. It is defined as amount of substance of a system that contains as many elementary particle as there are in 0.012 kg of carbon-12 (C-12)

DERIVED UNITSThe units that can be obtained from fundamental units are called derived units.Example Acceleration = velocity/Time = V/S = (m/s)/s = m/s2 = ms-2

Derived SI Units (examples)

Quantity unit SymbolVolume cubic meter m3

Density kilograms per cubic meter kg/m3

Speed meter per second m/sNewton kg m/ s2 NEnergy Joule (kg m2/s2) JPressure Pascal (kg/(ms2) Pa

Prefix /Scientific Notation:In Science the very large and very small units are expressed in numerical figures on

the base of 10. In this way we can read, write and calculate very easily these very large and very small figures.It is a modifier that allows us to express multiples or fractions of a base unit.In example we write that 1 metric ton weight = 1000 Kg or 1000000 grams But we can express these as 1 metric ton = 1.0x103 Kg or 1.0 x 106 grams

Number expressed as:o Product of a number between 1 and 10 and a power of 10

5.63 x 104, meaning 5.63 x 10 x 10 x 10 x 10 or 5.63 x 10,000

o ALWAYS has only ONE nonzero digit to the left of the decimal pointo ONLY significant numbers are used in the first numbero First number can be positive or negativeo Power of 10 can be positive or negative

When to Use Scientific Notation Astronomically Large Numbers

o mass of planets, distance between stars Infinite Small Numbers

o size of atoms, protons, electrons

Powers of 10 Positive Exponents Negative Exponents

Exponent of Zero Means “1” 100 = 1

SI Unit Prefixes: Positive exponents Negative exponentsName Symbo

lFactor

yotta Y 10 24

zetta Z 10 21

exa E 1018

peta P 1015

tera T 1012

giga G 109

mega M 106

kilo k 103 hecto h 102

deca da 10 1

Name Symbol Factordeci- d 10-1

centi- c 10-2

milli- m 10-3

micro- μ 10-6

nano- n 10-9

pico- p 10-12

femto- f 10-15

Atto a 10¯18

zepto z 10¯21 yocto y 10¯24

101=10102=10×10=100103=10×10×10=1000104=10×10×10×10=10 ,000

10−1=110

=0 .1

10−2=110

×110

=1100

=0. 01

10−3=110

×110

×110

=11000

=0 . 001

10−4=110

×110

×110

×110

=110 ,000

=0 .0001

SI Unit Prefixes for Length

Name Symbol

Factor

gigameter Gm 109

megameter Mm 106

kilometer km 103

decimeter dm 10-1

centimeter cm 10-2

millimeter mm 10-3

micrometer μm 10-6

nanometer nm 10-9

picometer pm 10-12

ADVANTAGES OF S.I.Units:

In international System the units are defined in length, mass, volume and time which are standardized and accepted in all scientific researches. In health sector this system is used to prescribe the medication, dosage, parenteral fluid volume maintenance, basal metabolic index calculations, percentages of blood configuration and measurements of vital signs, human body’s mass, fluids and different organs volumes and capacity, is measured in S.I. Units. All the books related to medical and scientific research explain their research results in S.I.Units and these are internationally accepted all over the world to scientific researching and consumers’ community.

Some conversions of units of length, mass and volume are: Length VolumeCentimeter 0.032808 foot=0.3937 inch=0.01

meterGallon 4 quart = 8 pints=

3.7853 litresFoot 12 inch- 0.3048 meter Litre 1000 milliliters =Inch 1/12 foot=1/36 yard

=25.40005millimetersMilliliter 0.001 litre= 1 milliliter

meter 39.37 inch=1.093611yards=3.290833feet

Pint ½ quart =16 fluid ounce =0.473167 litre

Millimeter 0.03937 inch=0.001 meter quart 2 pints =32 fluid ounce = 0.946333 litre

yard 3 feet=36 inch= 0.91440183 meterweightKilogram 1000 grams= 2.2046223 poundsMilligram 0.001 grampound 16 ounce = 453.5924 grams

UNIT NO.03WHAT IS MOTION?

Motion is a change in position of an object with respect to time.When a body is continuously changing its position with respect to the surroundings, then we say that the body is in motion.What are the different types of motion?Linear motion: when a body moves either in a straight line or along a curved path, then we say that it is executing linear motion. 1. When a body moves in a straight line then the linear motion is called rectilinear motion. E.g. an athlete running a 100 meter race along a straight track is said to be a linear motion or rectilinear motion. 2. When a body moves along a curved path then the linear motion is called curvilinear motion. e.g., a planet revolving around its parent starOther types of motion are:Rotatory motion: A body is said to be in rotatory motion when it stays at one place and turns round and round about an axis. Example: a rotating fan, a spinning top, the earth.Oscillatory motion: a body is said to be in oscillatory motion when it swings to and fro about a mean position. Example: the pendulum of a clock, the swing etc.What is the physics relating to motion called?Mechanics: it is an important branch of physics and deals with the effect of force on bodies. It is further divided into two parts

1. Dynamics: In dynamics we discuss the motion of bodies under the action of forces.

2. Kinematics: it deals with the study of motion of bodies without any reference to the cause of motion.

FORCE Force is an action /agent that can change motion of a body. Force is an action /agent that can change state of rest of a body.

— A force is what we call a push or a pull, or any action that has the ability to change an object’s motion.

— Forces can be used to increase the speed of an object, decrease the speed of an object, or change the direction in which an object is moving.

Centripetal force is the inward force exerted on an object to keep it moving in a curved path.

Centrifugal force is the outward force exerted on the object that makes it want to fly off into space

Inertia

Inertia is a term used to measure the ability of an object to resist a change in its state of motion.

An object with a lot of inertia takes a lot of force to start or stop; an object with a small amount of inertia requires a small amount of force to start or stop.

The word “inertia” comes from the Latin word inertus, which can be translated to mean “lazy.”

NEWTON’S LAWS OF MOTIONNewton's laws of motion are three physical laws which provide relationships between the forces acting on a body and the motion of the body.

1st Law – An object at rest will stay at rest, and an object in motion will remain in motion at constant velocity, unless acted upon by an unbalanced force.

2nd Law – Force equals mass times acceleration. 3rd Law – For every action there is an equal and opposite reaction.1st Law of Motion (law of inertia)An object at rest will stay at rest, and an object in motion will stay in motion at constant velocity, unless acted upon by an unbalanced force. Inertia is the tendency of an object to resist changes in its velocity: whether in motion

or motionless. Once air borne, unless acted on by an unbalanced force (gravity and air – fluid

friction), it would never stop! Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

Why then, do we observe everyday objects in motion slowing down and becoming motionless seemingly without an outside force?

It’s a force we sometimes cannot see – Friction. Objects on earth, unlike the frictionless space the moon travels through, are under the influence of friction.Friction

• There are four main types of friction:o Sliding friction: ice skatingo Rolling friction: bowlingo Fluid friction (air or liquid): air or water resistanceo Static friction: initial friction when moving an object

Slide a book across a table and watch it slide to a rest position. The book comes to a rest because of the presence of a force - that force being the force of friction - which brings the book to a rest position.

• In the absence of a force of friction, the book would continue in motion with the same speed and direction - forever! (Or at least to the end of the table top.)

Newton's Second LawThree forms of the second law:

Use If you want to find And you knowA= F/m The acceleration(a) The net force(F)and the mass(m)F= m/a The net force(F) Acceleration(a) and the mass(m)M=F/a The mass(m) The acceleration(a) and the net force(F)

Newton’s 2nd law The net force of an object is equal to the product of its mass and acceleration, or

F=ma. When mass is in kilograms and acceleration is in m/s/s, the unit of force is in newtons

(N). One Newton is equal to the force required to accelerate one kilogram of mass at one

meter/second/second.How much force is needed to accelerate a 1400 kilogram car 2 meters per

second/per second?Write the formula•F = m x a•Fill in given numbers and units•F = 1400 kg x 2 meters per second/secondSolve for the unknown•2800 kg-meters/second/second or 2800 N

Net ForceN

MassKilograms

Accelerationm/s/s

10 2 5 m/s/s20 2 10 m/s/s20 5 m/s/s20 5 m/s/s

1 10 m/s/s

Newton’s 2nd Law proves that different masses accelerate to the earth at the same rate, but with different forces.

• We know that objects with different masses accelerate to the ground at the same rate.• However, because of the 2nd Law we know that they don’t hit the ground with the same force.

M= 10 Kg

a= Fm

a= 98N10kg

A=9.8 m/s2

M= 1 Kg

a= Fm

a=9.8N1kg

A=9.8 m/s2

F = ma98 N = 10 kg x 9.8 m/s/s

F = ma9.8 N = 1 kg x 9.8 m/s/s

Newton's third Law For every action, there is an equal and opposite reaction.According to Newton, whenever objects A and B interact with each other, they exert forces upon each other. When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body.There are two forces resulting from this interaction - a force on the chair and a force on your body. These two forces are called action and reaction forces.Newton’s 3rd Law in Nature

• Consider the propulsion of a fish through the water. A fish uses its fins to push water backwards. In turn, the water reacts by pushing the fish forwards, propelling the fish through the water.

• The size of the force on the water equals the size of the force on the fish; the direction of the force on the water (backwards) is opposite the direction of the force on the fish (forwards).

• Flying gracefully through the air, birds depend on Newton’s third law of motion. As the birds push down on the air with their wings, the air pushes their wings up and gives them lift.

• Consider the flying motion of birds. A bird flies by use of its wings. The wings of a bird push air downwards. In turn, the air reacts by pushing the bird upwards.

• The size of the force on the air equals the size of the force on the bird; the direction of the force on the air (downwards) is opposite the direction of the force on the bird (upwards).

• Action-reaction force pairs make it possible for birds to fly.• Consider the motion of a car on the way to school. A car is equipped with wheels which spin

backwards. As the wheels spin backwards, they grip the road and push the road backwards.• The reaction of a rocket is an application of the third law of motion. Various fuels are burned

in the engine, producing hot gases. • The hot gases push against the inside tube of the rocket and escape out the bottom of the

tube. As the gases move downward, the rocket moves in the opposite direction.

SPEED, VELOCITY, ACCELERATION AND ACCELERATION DUE TO GRAVITYIntroductionKinematics is the science of describing the motion of objects using words, diagrams, graphs, and equations. The goal of kinematics is to develop mental models to describe the motion of real-world objects.The motion of objects can be described by words. Even a person without a background in physics has a collection of words, which can be used to describe moving objects. For example, going faster, stopped, slowing down, speeding up, and turning provide a sufficient vocabulary for describing the motion of objects. In physics, we use these words as the language of kinematics. 1. Distance and Displacement 2. Speed and Velocity3. AccelerationThese words which are used to describe the motion of objects can be divided into two categories.The quantity is either a vector or scalar.1. Scalars are quantities which are described by a magnitude only.2. Vectors are quantities which are described by both a magnitude and a direction.

Distance: length between two points in a straight line or length moved through a definite path. Distance refers to the total length of travel irrespective of the direction of the motion.Displacement: Distance moved in a definite direction (vector quantity). Displacement refers to the distance moved in a particular direction. It is the object's overall change in position. In physics, the word position refers to the location of an object at one instant. A position is always specified relative to an origin. The net change in position relative to the origin is called displacement.

Distance Displacement• Distance refers to the total length of travel irrespective of the direction of the motion.• It is a scalar quantity. • SI unit: metre (m)• Other common units: kilometre (km), centimetre (cm)

• Displacement refers to the distance moved in a particular direction. • It is the object's overall change in position.• It is a vector quantity. • SI unit: metre (m)• Other common units: kilometre (km), centimetre (cm)

Example 1A student walks 4 m East, 2 m South, 4 m West, and finally 2 m North. Total distance = 12 mDuring the course of his motion, the total length of travel is 12 m. Total displacement = 0 m When he is finished walking, there is no change in his position. The 4 m east is “canceled by” the 4 m west; and the 2 m south is “canceled by” the 2 m north.

SPEED Definition: Rate at which an object moves• Speed is a measure of how fast something is moving.• It is the rate at which a distance is covered• Units of speed could be: km/h, m/s, mi/h, ft/s• In physics we use units of m/s for speed

Speed= distance time

s = d/tInstantaneous Speed• Instantaneous speed is speed at any instant in time.

• A speedometer measures speed in ‘real time’ (the instantaneous speed).

Constant speed - speed that doesn’t changeAverage Speed• Average speed is the average of all instantaneous speeds; found simply by a total distance/total time ratioThe average speed of the entire journey can be calculated:

Average Speed=Total distance travelledTotal time taken

VELOCITYVelocity is the distance travelled in a specific direction.• Velocity is defined as speed in a given direction or rate of change of position (displacement over time). v = x/t • Velocity refers to both the speed and direction of motion of an object (a vector quantity).• Negative velocity means the object is moving in the opposite direction• Motion at constant velocity means that both the speed and direction of an object do not change.• In a car, we can change the velocity three ways: gas pedal to speed up, brake to slow down or steering wheel to change direction

Speed VelocitySpeed is the rate of change of distance.speed has no direction It is a scalar quantity.

Speed= distance time

• Speed refers to how quickly an object moves (a scalar quantity).• (it is a scalar quantity

Velocity is the distance travelled in a specific direction. It is also defined as the rate of change of displacement. It is a vector quantity.

Velicoty=Change in displacement in a direction time taken

• Velocity is defined as speed in a given direction or rate of change of position (displacement over time). v = x/t • Velocity refers to both the speed and direction of motion of an object (a vector quantity).• Velocity at any instant is simply the speed with a direction.

An object is moving in a circle at a constant speed of 10 m s-1. We say that it has a constant speed but its velocity is not constant.

WHY The direction of the object keeps changing.

Acceleration• For its velocity to change, an object must accelerate.• An object accelerates whenever its speed or direction or both change.• Acceleration may be positive (increasing speed) or negative (decreasing speed).

• Units: m/s/s or km/s/s

• Acceleration is a measure of how quickly the velocity changes: a = Dv/t

acceleration=change of velocity time interval

a = (Vf – Vi) ¸ t or where Vf = Final velocity and Vi = initial velocity

a =

v- ut

where a = acceleration, v =final velocity, u = initial velocity and t = time. Acceleration at constant speed• An object moving in a circle at constant speed is always accelerating (changing direction).ACCELERATION DUE TO GRAVITY, G• Newton told us that every object with mass attracts every other object with mass and the

size of the attraction depends on the mass of each object and the distance between the objects

• We don’t feel the attraction of most objects because their mass is small relative to the Earth which has a huge mass.

• The Earth pulls so that objects experience an acceleration of about 9.8 m/s2. This acceleration is given a special letter, g. and it is = 9.8 m/s2

• So during each second an object is in free fall, its velocity increases by 9.8 m/s. If the object experiences air resistance its velocity won’t increase as fast because air resistance will slow it down.

The unit of FORCE is in Newton (N). The ACCELERATION due to gravity is given a special letter, g. and it is = 9.8 m/s2 Units of speed could be: km/h, m/s, mi/h, ft/s Unit of Distance: SI unit: metre (m) Other common units: kilometre (km),

metres,centimetre (cm) Unit of Displacement: SI unit: metre (m) Other common units: kilometre (km), centimetre

(cm) Unit of Acceleration: SI unit: m/s2

Friction Friction is a force between two surfaces that are sliding, or trying to slide across one another, for example when you try to push a toy car along the floor.

When a body slides over the surface of another body, an opposing force is set up between them to resist    the motion. The force which opposes the motion is called friction OR Force of Friction.

   Force of friction tends to decelerate a body and always acts in the opposite direction of motion.

• Friction always works in the direction opposite from the direction the object is moving, or trying to move. It always slows a moving object down.

• The amount of friction depends on the materials from which the two surfaces are made. The rougher the surface, the more friction is produced. For example, you would have to push a book harder to get it moving on a carpet than you would on a wooden floor. This is because there is more friction between the carpet and the book than there is between the wood and the book.

• Friction also produces heat. For example, if you rub your hands together quickly, they get warmer.

“Friction is a Force that always pushes against an object when it touches another object”Cause of Friction: the microscopic roughness between surfaces…like two gears locking together. High friction (lots of friction) – will slow something down Low friction (not much friction) – will keep things moving

Types of friction Static Sliding Rolling Fluid

Static Friction that acts on something that is not moving Piano is held in place by static friction Static friction keeps you in your seat No heat is generated.

Dry friction: occurs when non smooth (non ideal) surfaces of two solids are in contact under a condition of sliding or a tendency to slide.Static Friction – Static > Kinetic energy Kinetic Friction So… it takes more force to start moving an objectSliding

Force resulting when pushing or pulling an object over a surface. Moving day—pushing a box across the floor Heat can result

Rolling Contact is reduced because of rollers or wheels or ball bearings. Skate boards have ball bearings in the wheels. A cart has wheels. Less heat and wear will result.

Rolling Friction – (< sliding) wheels and ball bearingsFluid friction Resistance from a “liquid” or air. Walking or swimming through water Olympic bike riders

Characteristics of Sliding Friction1. Friction acts parallel to the surface and opposite of the motion! 2. Friction depends on the type of materials in contact! 3. Sliding friction is always less than starting (static) friction! 4. Friction is independent of the surface area in contact!5. Friction depends upon the Normal Force!

ADVANTAGES OF FRICTIONFriction plays a vital role in our daily life. Without friction we are handicap.

1. It is becomes difficult to walk on a slippery road due to low friction. When we move on ice, it becomes difficult to walk due to low friction of ice.

2. We can not fix nail in the wood or wall if there is no friction. It is friction which holds the nail.3. A horse can not pull a cart unless friction furnishes him a secure Foothold.DISADVANTAGES OF FRICTION Despite the fact that the friction is very important in our daily life, it also has some disadvantages like:1. The main disadvantage of friction is that it produces heat in various parts of machines. In this

way   some useful energy is wasted as heat energy.2. Due to friction we have to exert more power in machines.3. It opposes the motion. 4. Due to friction, noise is also produced in machines.5.  Due to friction, engines of automobiles consume more fuel which is a money loss. 

METHODS OF REDUCING FRICTIONthere are a number of methods to reduce friction in which some are discussed here.USE OF LUBRICANTS:The parts of machines which are moving over one another must be properly lubricated by using oils and lubricants of suitable viscosity. 

1. USE OF GREASE: Proper greasing between the sliding parts of machine reduces the friction.USE OF BALL BEARING:

2. In machines where possible, sliding friction can be replaced by rolling friction by using ball bearings. 

3. DESIGN MODIFICATION: Friction can be reduced by changing the design of fast moving objects. The front of vehicles and airplanes made oblong to minimize friction.

APPLICATIONS OF FRICTION IN NURSING AND DAILY LIFE Whenever friction occurs between two contacting surfaces, the friction occurs. Friction is undesirable but it is beneficial in many situations. Friction plays a vital role in our daily life. Without friction we are handicap. It is becomes difficult to walk on a slippery road due to low friction. When we move on ice, it

becomes difficult to walk due to low friction of ice. It is friction which holds the nail in the wood or wall. A horse cannot pull a cart unless friction furnishes him a secure Foothold.

The friction normally produced by the soles of the shoes over the rough surface of the street, eases to walk, run or jogging, if the resistance is lessened, the pedestrians can easily slip about.

The ability to grasp objects in hands is due to the friction provided by the ridges of the fingers and hands.

It is difficult to walk over plain and slippery flours for the staff in hospitals so the floors are designed with somewhat frictional properties.

Without friction we cannot burn a stick over match.

UNIT NO.04GRAVITY AND STABILITY

GRAVIRY There is a power of gravity pertaining to all bodies in the universe, proportional to the

several quantities of matter which they contain. The force acts in the direction of the line connecting the centers of their masses. Gravity is defined as the force which gives freely falling objects on or near the surface of the

earth with acceleration. On the earth its value is 9.8m/sec2.

Every object in our universe attracts the other object with certain fore towards its center. Any two objects attract each other with a gravitational force, proportional to the product of

their masses and inversely proportional to the square of the distance between them. The force acts in the direction of the line connecting the centers of the massesThis force of attraction is known as gravitational force and the phenomenon is called gravitation. This is gravitational force which is responsible for the uniformity or regularity in our daily

astronomical life. The whole system of the universe is in order only due to this force. Due to gravitation, the

system of our universe is working uniformly and smoothly. The planets around the earth or around the sun move in an orderly motion due to gravitation.

NEWTON’S LAW OF GRAVITATIONIn order to explain the gravitational force between two bodies, Newton formulated in 1667 a fundamental law known after his name i.e. "NEWTON'S LAW OF GRAVITATION".Newton’s law of gravitation states that every object in the universe attracts the other object with a force and the gravitational force of attraction between two bodies is directly proportional to the product of their masses. F  ∝m1 x m2 ------- (1)

(1)  The gravitational force of attraction between two bodies is inversely proportional to the square of the distance between their centers.

F ∝1/d2 --------- (2)

MATHEMATICAL REPRESENTATIONCombining (1) and (2)F ∝m1m2 /d2

F = G m1m2/d2

F=Gm 1×m2

d2

Where G = universal gravitational constantValue of G: Henry Cavendish’s experiment determined the proportionality constant G in 1798.G = 6.67 x 10-11 Nm2/kg2

Change of Gravitational Force with Distance

Law of universal gravitation is known as an inverse square law.

The change in gravitational force with distance follows the inverse square law

CENTRE OF GRAVITY Center of gravity of a body is a point where total weight of the body is concentrated. The center of a body is that point in the body through which the resultant forces due to the

earth’s attraction posses and through which the whole weight of the body always acts. Every body posses a center of gravity and this is irrespective of the body. It is not necessary

that the center of gravity should be within the body, but it may also be situated in space outside the body. Example: center of gravity of a ring is at the center, which is in the space.Near the surface of the earth, the force of gravity is the same on all parts of the body. This means that the center of gravity and center of mass of an object are the same location.

It is Balance point of the body. Point about which the body rotates while free in the air. Point of the body where we can consider all of the weight of the body to act.

  A uniform stick

There are numerous particles in the stick that each have a mass. Gravity acts on all of these masses producing forces which act at a distance from the center of gravity. Because these forces act at a distance, they produce a torque. The point where all these torques balance out is the center of gravity.

 CENTER OF GRAVITY OF DIFFERENT REGULAR OBJECTS:There are three different axes about which an object will naturally spin. The point at which the three axes intersect is called the center of gravity or center of mass. Rectangle

   Center of gravity of a rectangular is at the point of intersection of its diagonals Circle

   Center of gravity of a circle is at its center. Square

   Center of gravity of square is at the point of intersection of its diagonals. Regular bar

   The center of gravity of a regular bar is at its geometrical center. Triangle

   The center of gravity of a triangle is at the point of intersection of its medians. Cylinder

   The center of gravity of a cylinder is at the axis of cylinder.

   CENTER OF GRAVITY OF DIFFERENT IRREGULAR OBJECTS:

There are three different axes about which an object will naturally spin.

The point at which the three axes intersect is called the center of mass.

If an object is irregularly shaped, the center of mass can be found by spinning the object and finding the intersection of the three spin axes.

There is not always material at an object’s center of mass.

FINDING THE CENTER OF GRAVITY OF AN IRREGULARLY SHAPED OBJECT The center of gravity of an irregularly shaped object can be

found by suspending it from two or more points.

For very tall objects, such as skyscrapers, the acceleration due to gravity may be slightly different at points throughout the object.

APPLICATION OF GRAVITY IN DAILY LIFE AND NURSING The force of gravity is so much the part of our daily life that it is difficult to comprehend its

absence.

Without gravity there would be no pressure in liquids, and therefore no irrigations, intravenous infusions, or blood transfusion would be possible.

Circulation of the blood depends on gravity. The blood pressure in the blood vessels of head and neck is slightly less than the lower

extremities. Changing in positions of body alignments, alter the blood pressure in different parts of the body. In a fainting spell, the brain is temporarily deprived of blood. But when the person feels faint the

same effect may be accomplished by lowering the head. The effects of gravity are visible in the blanching of the upraised hand and in the reddening and

venous distension of the other hand. Gravity exercises are sometimes prescribed for patients with circulatory disorders of the lower

extremities. These exercises consist of alternately swinging the legs over the side of the bed. The change in position aids in improving circulation of the blood. An electrically driven oscillating bed may be used in the treatment of circulatory disorders . Postural drainage is a treatment in which the patient lies on his abdomen across the bed with his

chest and head hanging down over the side of the bed. It utilizes the gravity to affect drainage from the lungs.

Patients are placed pre operative and postoperative in a special positions due to gravity. After operation on the throat or mouth the patient’s head is usually lowered and placed to one

side so that the mucus and fluids will drain out of the mouth by gravity. Brain surgery is frequently done in sitting or semi-sitting position to lessen the danger of

hemorrhage. After thoracic surgery the patient is placed in semi sitting position to increase drainage from the

thorax through the drainage tube by gravity. A diagnostic test ESR erythrocyte sedimentation rate is done on the base of gravity The blood is mixes with sodium citrate or sodium oxalate and then it is kept in a log thin glass

tube. The weak RBCs sediment fastly and it is the sign of presence of a chronic disease and if these RBCs sediment slowly and up to normal limit .it shows absence of such disease.

EquilibriumA body is said to be in equilibrium if it is at rest or moving with uniform velocity.   In other words if the linear and angular acceleration of a body are zero, the body is said to be in equilibrium.    Or we can say that when two or more forces act on a body such that their resultant or combining effect    on the body is Zero and the body retains its state of rest or of uniform motion then the body is said to    be in equilibrium.Example: A book lying on the table, suspended bodies, all stationary bodies , jump by using parachute.Types of equilibriumWith respect to the state of a body, equilibrium may be divided into two categories:   1. Static equilibrium.   2. Dynamic equilibrium.Static equilibriumIf the combined effect of all the forces acting on a body is zero and the body is in the state of rest then    its equilibrium is termed as static equilibrium.    For example: All stationary bodiesDynamic equilibriumWhen a body is in state of uniform motion and the resultant of all the forces acting upon it is zero then it    is said to be in dynamic equilibrium.    For example: Jump by using parachute.

CONDITIONS OF EQUILIBRIUMThere are two conditions of equilibrium are as follows

First condition of equilibrium:The first condition of equilibrium stated as follow:To maintain the transitional equilibrium in a body the vector sum of all the forces acting on the body is equal to zeroIn other words we can say that to maintain equilibrium the sum of all the forces acting along X-axis is zero and the sum of all the forces acting along Y-axis is zero.Second condition of equilibriumThe second condition of equilibrium stated as follow:A body will be in rotational equilibrium when the algebraic sum of clock wise torque and anti clock wise torque is zero. In other words it can be stated that a body will be in rotational equilibrium if vector sum of all the torque acting on the body is zero.STATES OF EQUILIBRIUMThere are three states of equilibrium:1. Stable equilibrium 2. Unstable equilibrium3. Neutral equilibrium

Stable equilibriumWhen the center of gravity of a body lies below point of suspension or support, the body is said to be in    STABLE EQUILIBRIUM. For example a book lying on a table is in stable equilibrium.Explanation:   A book lying on a horizontal surface is an example of stable equilibrium. If the book is lifted from one edge    and then allowed to fall, it will come back to its original position.   Other examples of stable equilibrium are bodies lying on the floor such as chair, table etc.

1. Reason of stabilityWhen the book is lifted its center of gravity is raised . The line of action of weight passes through the    base of the book. A torque due to weight of the book brings it back to the original position.

2. Unstable equilibriumWhen the center of gravity of a body lies above the point of suspension or support, the body is said to    be in unstable equilibrium Example pencil standing on its point or a stick in vertically standing position.Explanation:   If thin rod standing vertically is slightly disturbed from its position it will not come back to its original    position. This type of equilibrium is called unstable equilibrium, other example of unstable equilibrium are    vertically standing cylinder and funnel etc.

Reason of instabilityWhen the rod is slightly disturbed its center of gravity is lowered . The line of action of its weight lies outside the base of rod. The torque due to weight of the rod toppled it down.3. Neutral equilibriumWhen the center of gravity of a body lies at the point of suspension or support, the body is said to be in    neutral equilibrium. Example: rolling ball.Explanation If a ball is pushed slightly to roll, it will neither come back to its original nor it will roll forward rather it will    remain at rest. This type of equilibrium is called neutral equilibrium. Reason of neutral equilibrium

If the ball is rolled, its center of gravity is neither raised nor lowered. This means that its center of gravity    is at the same height as before.

Placement of the Center of Gravity in Humans The location of the CG of a human being in the normal standing position varies with body build,

age, and sex Male’s CG is ~57% of standing height In quiet standing, the CG can be considered to be almost directly over the center of pressure Center of pressure is the point at which the force vector for ground reaction force is applied Female’s CG is ~ 55% of standing height

Adjusting the Center of GravityHumans spend most of their time adjusting their positions to the type of equilibrium best suited to the task and environmentFactors Affecting Stability The ability to maintain one’s balance under unfavorable circumstance is recognized as one of

the basic motor skills The following factors affecting the stability of a performer’s equilibrium state

– should make analysis easier– may suggest means for improvement

Horizontal Center of Gravity There are different types of support systems in order to maintain equilibrium and stability Size of the base of Support CG must remain within the base of support in order to maintain stable and in equilibrium Easier with larger base of support Shape of the base of Support Base of Support Both feet and hands a quadruped Babies crawl, roll and sprawl in their form of locomotion Children and adults biped Seniors quadruped with the help of a walker Age and fitness specificVertical Center of Gravity Height and location of Center of Gravity along a vertical line (y axis) Height of the Center of Gravity Height of Center of Gravity (CG) Height of CG changes with body position along the vertical line As CG moves closer to base of support more angular displacement can occur before it goes

beyond the base of supportRelationship of the Line of Gravity to the Base of Support To maintain equilibrium, line of gravity must remain within its base of support Mass of the Body Only a factor when motion or an external force is involved Amount of force needed to effect a change in motion is proportional to the mass being moved The greater the mass, the greater the stabilityFriction Friction is related to the size of the base of support It has greater influence when body is in motion or being acted on by an external force Inadequate friction makes it more difficult to maintain equilibrium Segmental Alignment The human body consists of a series of segments placed one above the other, the problem of

retaining equilibrium is a multiple one When segments are aligned in a single vertical line, there is less likely hood of strain to joints

and muscles When one segment gets out of line, another segment must compensate for it

Visual and Psychological Factors The effect of crossing a swirling river on a foot bridge is a detriment to one’s equilibrium Even if the supporting surface is adequate The sense of balance may be disturbed, extraordinary stimuli Compensation: fix eyes on a stationary spot above or beyond the “danger area” Seems to facilitate neuromuscular control by reducing the disturbing stimuliPhysiological Factors Semicircular canals can affect equilibrium

– Colds, viruses, and other problems can affect the inner ear may also interfere with balance

Any disturbance of the general physical condition is likely to affect the sense of balance

TORQUETorque, moment or moment of force (see the terminology below), is the tendency of a force to rotate an object about an axis fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist to an object.Loosely speaking, torque is a measure of the turning force on an object such as a bolt or a flywheel. For example, pushing or pulling the handle of a wrench connected to a nut or bolt produces a torque (turning force) that loosens or tightens the nut or bolt.The symbol for torque is typically τ, the Greek letter tau. When it is called moment, it is commonly denoted M.The magnitude of torque depends on three quantities: the force applied, the length of the lever arm connecting the axis to the point of force application, and the angle between the force vector and the lever arm. In symbols:

Torque A torque is an action that causes objects to rotate. Torque is not the same thing as force. For rotational motion, the torque is what is most directly related to the motion, not the force.

Motion in which an entire object moves is called translation.

Motion in which an object spins is called rotation.

The point or line about which an object turns is its center of rotation.

An object can rotate and translate.

Torque is created when the line of action of a force does not pass through the center of rotation.

The line of action is an imaginary line that follows the direction of a force and passes though its point of application.

To get the maximum torque, the force should be applied in a direction that creates the greatest lever arm.

The lever arm is the perpendicular distance between the line of action of the force and the center of rotation

Balancing torques

Left torque = 10 N x 1 m = 10 N m

10 N 20 N

1 m 0.5 m

Right torque = 20 N x 0.5 m = 10 N mBy using the formula F 1X d1 = F2X d2

MOMENTUM- LAW OF CONSERVATION OF MOMENTUM

MOMENTUMQuantity of motion of a body is referred to as "MOMENTUM".DefinitionMomentum of a moving body defined as :"the product of mass and velocity of a body is called MOMENTUM."MathematicallyMomentum = mass x velocity

It is a vector quantity. Momentum is always directed in the direction of velocity. The unit of momentum is in S.I system kg .m/s or NS.  Momentum depends upon mass and velocity of body.LAW OF CONSERVATION OF MOMENTUM.The law of conservation of momentum states that:"When some bodies constituting an isolated system act upon one another, the total momentum of the system remains constant." OR"The total momentum of an isolated system of interacting bodies remains constant." OR"Total momentum of an isolated system before collision is always equal to total momentum after collision."Consider an isolated system of two bodies 'A' and 'B' as shown. The masses of bodies are ma and mb MATHEMATICAL REPRESENTATIONConsider two bodies of mass m1 and m2 moving initially with velocities u1 and u2.

Total momentum before collision = m1u1 + m2u2

Let after collision their velocities become v1 and v2.

Total momentum after collision = m1v1 + m2v2

According to the law of conservation of momentumm1u1 + m2u2 = m1v1 + m2v2

UNIT NO.05WORK, POWER AND ENERGY

ENERGY Energy can be defined as the capacity for doing work. Energy can be defined as the ability to do work.

If an object or organism does work (exerts a force over a distance to move an object) the object or organism uses energy.

Nature of Energyo Because of the direct connection between energy and work, energy is measured in the same

unit as work: joules (J).o In addition to using energy to do work, objects gain energy because work is being done on

them.

USES OF ENERGY Ability to do work or cause change Produces Warmth Produces Light Produces Sound Produces Movement Produces Growth Powers Technology

Forms/ States of EnergyThere are two main states of energy in many forms:1. Kinetic Energy 2. Potential Energy

Kinetic Energy :Energy of Motion The energy of a moving object is called kinetic energy. Everything you see moving about has kinetic energy.  The kinetic energy of an object in this case is given by the relation: K.E = (1/2)mv2

m=mass of the object V=velocity of the object For an object of mass m, moving with velocity of magnitude v, this energy can be calculated from the formula o The faster an object moves, the more kinetic energy it has.o The greater the mass of a moving object, the more kinetic energy it has.o Kinetic energy depends on both mass and velocity.

Potential Energy: stored energyo Substances like wood, coal, oil, and gasoline have stored energy as Potential energy because of

their chemistry – they can burno Stored energy is potential energy ,it can be changed into Kinetic Energy

o Also Kinetic Energy can be changed into Potential EnergyPotential energy exists whenever an object which has mass has a position within a force field. The most everyday example of this is the position of objects in the earth's gravitational field. The potential energy of an object in this case is given by the relation: PE = mgh  PE = Energy (in Joules) m = mass (in kilograms)

g = gravitational acceleration of the earth (9.8 m/sec2) h = height above earth's surface (in meters)

Gravitational Potential Energyo Potential energy that is dependent on height is called gravitational potential energy.o Energy that is stored due to being stretched or compressed is called elastic potential energy.o A waterfall, a suspension bridge, and a falling snowflake all have gravitational potential energy.o “The bigger they are the harder they fall” is not just a saying. It’s true. Objects with more mass

have greater G.P.E.o The formula to find G.P.E. is

G.P.E. = Weight X Height.

The seven types of energy1. Chemical - gasoline, food2. Light – flash light, 3. Heat – burner on a stove, 4. Nuclear - sun, 5. Mechanical - car, 6. Sound – music on the radio, 7. Electrical – lightning

Chemical EnergyChemical energy is the energy stored in the bonds of atoms and molecules. This form of potential energy, related to the breaking and forming of chemical bonds. It is stored in food, fuels and batteries, and is released as other forms of energy during chemical reactions.Fossil fuels and biomass store chemical energy. Products that contain chemical energy include: TNT, baking soda, and a match. Biomass, petroleum, natural gas, propane and coal are examples of stored chemical energy.o Chemical Energy is required to bond atoms together.o And when bonds are broken, energy is released. The chemical bonds in a matchstick store energy that is transformed into thermal energy when the match is struck

Electromagnetic Energy• energy that travels in waves; have electrical and magnetic properties• Light, Magnetism, X-Rays, Radio waves, microwaves, ultraviolent and infrared radiation, o It is a type of Kinetic energy. o Power lines carry electromagnetic energy into your home in the form of electricity.o Light is a form of electromagnetic energy.o Each color of light (VIBGYOR) represents a different amount of electromagnetic energy.o Electromagnetic Energy is also carried by X-rays, radio waves, and laser light.o High power rays are harmful to human and animals

Light is the movement of photonsoLight is a type of electromagnetic radiation. oLight travels in straight lines. oLight travels in transverse waves. oLight transmits ENERGY.oOur Sun (a star) is a light source, just like a filament lamp or a firefly.oViolet colour of light has the most energy.

Radiant energy It is also called electromagnetic energy. Radiant energy is the movement of photons. All life on earth is dependent on radiant energy from the sun. Examples of radiant energy include radio waves (AM, FM, TV), microwaves, X-rays, and solar radiation. Active solar energy uses photovoltaic panels and light to turn radiant energy into chemical energy. The chloroplast of plants converts CO2 and Water using solar radiation as energy to form glucose for plant growth.Magnetic energy is the attraction of objects made of iron. Medical equipment, compass, refrigerator magnets are all examples of magnetic energy. Any type of energy source that uses a generator in the process to make electricity uses magnetic energy. Heat /Thermal EnergyThermal energy is the internal energy in substances-the vibration and movement of atoms and molecules within substance. Thermal energy is created in the movement of atoms. Boiling water, burning wood, and rubbing your hands together really fast are all examples of heat energy. Geothermal and passive solar are sources of heat energy, but biomass (a type of chemical energy) can be burned to produce heat energy. o The internal motion of the atoms is called heat energy, because moving particles produce heat.o Heat energy can be produced by friction.o Heat Energy is a form of energy that is transferred by a difference in temperatureo Heat energy causes changes in temperature and phase of any form of matter.o The heat energy of an object determines how active its atoms are. A hot object is one whose atoms and molecules are excited and show rapid movement. A cooler object's molecules and atoms will show less movementMechanical energyMechanical energy is the Energy of the moving parts a machine. Also refers to movements in humans• Mechanical energy is also the total amount of kinetic and potential energy in a system. Wind-

up toys, grandfather clocks, and pogo sticks are examples of mechanical energy. Wind power uses mechanical energy to help create electricity.

• Potential energy + Kinetic energy = Mechanical energyo When work is done to an object, it acquires energy. The energy it acquires is known as

mechanical energy.o When you kick a football, you give mechanical energy to the football to make it move.When you throw a balling ball, you give it energy. When that bowling ball hits the pins, some of the energy is transferred to the pins (transfer of momentum).Sound Energy• Sounds are caused by vibrations and travels in longitudinal waves. • Sound transmits energy.

• Sound is the movement of energy through substances in the form of longitudinal / compression waves.

• Sound is the movement of molecules in the air that produces vibrations. Alarms, music, speech, ultrasound medical equipment all use sound energy. VCR tapes change sound energy into electrical energy. The electrical energy records the sound using magnetic tape. Speakers read the magnetic tape and change it back into sound. The louder the sound, the more energy it transmits.The quieter the sound, the less energy

Electrical EnergyElectrical energy is caused by the movement of electrons. Lightning in clouds and static electricity are examples of electrical energy that occur naturally. Science hasn't found a way to use natural forms of electrical energy, like lightning. Instead, we use different energy sources to create electrical energy by using generators and turbines. o Easily transported through power lines and converted into other forms of energyo It is the type of kinetic energy.Electricity is so useful because it is such a convenient way to transfer energy to a desired location or to a desired device.The generation or use of electric power over a period of time expressed in kilowatt-hours (kWh), megawatt-hours (NM) or gigawatt-hours (GWh).

Nuclear energyNuclear energy is the most concentrated form of energy.Nuclear energy is the energy stored in the nucleus of an atom. Nuclear energy is unusual in that it can give off energy in the form of light or heat, but it is the change in the atom's makeup that produces the energy. When atomic nuclei join together it is known as nuclear fusion. When atomic nuclei are split apart it is known as nuclear fission.Nuclear fission powers nuclear power station and atomic weapons. Submarines, power plants, and smoke detectors all use nuclear energy. Nuclear power plants use uranium, a radioactive element, to create electricity. Nuclear fusion powers the Sun and other stars. The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.1 Kg of Uranium produces energy through nuclear fission equal to the burning of 25 lac Kgs of Coal in an atomic reactor.

LAW OF CONSERVATION OF ENERGYEnergy can neither be created nor destroyed. Energy is always changing from one kind to another. The total energy of an object never changes.• Potential energy + Kinetic energy = Total energy• Total energy – Kinetic energy = Potential energy• Total energy - Potential energy = Kinetic energy

Energy will always transfer from high to low. No energy transfer is 100% efficient.

o Energy can be changed from one form to another. Changes in the form of energy are called energy conversions.

o All forms of energy can be converted into other forms.• The sun’s energy through solar cells can be converted directly into electricity.• Green plants convert the sun’s energy (electromagnetic) into starches and sugars (chemical

energy).• In an electric motor, electromagnetic energy is converted to mechanical energy.• In a battery, chemical energy is converted into electromagnetic energy.• The mechanical energy of a waterfall is converted to electrical energy in a generator. • In an automobile engine, fuel is burned to convert chemical energy into heat energy. The

heat energy is then changed into mechanical energy.

WORKWork is the transfer of energy through motion. In order for work to take place, a force must be exerted through a distance. The amount of work done depends on two things: the amount of force exerted and the distance over which the force is applied. There are two factors to keep in mind when deciding when work is being done: something has to move and the motion must be in the direction of the applied force. Work can be calculated by using the following formula: Work=force x distance , W= F X SW= work done, F = force applied, S = displacement in the direction of force. SI unit for work = Joule (J), other unit = Nm When work is done to an object, energy is transferred to the object.  Work is not done when: The object is stationary and not moving No force is applied on the object in the direction of displacement. The direction of motion of the object is perpendicular to that of the applied force. Kinetic energy or work done is given by:  ½ Mv2  M = mass, v = velocity  Unit: Joule /kgm2s-2

Efficiency Efficiency of a device is defined as the percentage of the energy input that is transformed into useful energy. Efficiency = (useful Energy output / Energy input ) X 100% Efficiency = (Useful power output / Power input) X 100% Unit is given in percentage. You must know the importance of maximising the efficiency of device. Power, Energy and EfficiencyPOWERPower is defined as the rate of doing work.  The SI unit of power is watt (w).1 watt is defined as the power required to perform 1 joule of work in 1 second.Power depends on the time taken and the work done .People or engine with high power rating can get the work done in short time.For a force F which produces a constant velocity, V,or a stationary object , the power generated is:

  P= Fv  Proof:    Power=  Work /  Time  = (Force x Displacement) /  Time     =Force x ( Displacement/  Time)   = Force x velocity  P= Fv

MACHINES AND THEIR FUNCTIONSAncient people invented simple machines that would help them overcome resistive forces and allow them to do the desired work against those forces easily. Simple machines are useful because they can make a physical job easier by changing the magnitude or the direction of the force exerted to do work. All of the simple machines can be used for thousands of jobs. The reason why these machines are so special is because they make difficult tasks much easier.

e.g. Have you ever tried to unscrew a nut, bolt, or screw from something with your bare hands and discovered that it was just too tight to loosen even if you had a good grip?

Simple machines are machines with few or no moving parts. A machine is a device that helps make work easier to perform by accomplishing one or more of

the following functions: transferring a force from one place to anothertransferring a force from one place to another, changing the direction of a force, increasing the magnitude of a force, or Increasing the distance or speed of a force.

Simple Machines can be put together in different ways to make complex machinery Simple machines are important to us in our daily life. They help us do work. They make our lives easier.

Mechanical Advantage It is useful to think about a machine in terms of the input force (the force you apply) and the

outputforce (force which is applied to the task). When a machine takes a small input force and increases the magnitude of the output force, a

mechanical advantage has been produced. Mechanical advantage is the ratio of output force divided by input force. If the output force is

bigger than the input force, a machine has a mechanical advantage greater than one. If a machine increases an input force of 10 pounds to an output force of 100 pounds, the

machine has a mechanical advantage (MA) of 10.

In machines that increase distance instead of force, the MA is the ratio of the output distance and input distance.

MA = output/input No machine can increase both the magnitude and the distance of a force at the same time.

WORK INPUT AND OUTPUT Work input is the amount of work done on a machine.

o Input force x input distance Work output is the amount of work done by a machine.

o Output force x output distance

EFFICIENCY Efficiency of a device is defined as the percentage of the energy input that is transformed into

useful energy.  The comparison of work input to work output is called efficiency.

Input Force x Distance = Output Force x Distance No machine has 100 percent efficiency because some output force is lost due to friction. Efficiency = (useful Energy output / Energy input ) X 100% 

Efficiency = (Useful power output / Power input) X 100% Unit is given in percentage. You must know the importance of maximizing the efficiency of device. Power, Energy and Efficiency

EFFICIENCY OF MACHINES

1. Machines are devices that make our work easier.2. Machines require energy to work. This energy is called the input.3. Machines transform this input into other forms of energy to perform useful works.4. However, the useful work obtained is not equal to the input as there is energy “loss” In this

process. This loss is mainly due to work done against frictional forces and takes the forms of heat.

5. So, a machine is not perfect because the work done by the effort or input energy is not wholly used to overcome the load.

THE 6 SIMPLE MACHINES1. Lever2. Inclined Plane3. Wedge4. Screw5. Wheel and Axle6. Pulley

1. THE LEVER A lever is a rigid bar that rotates around a fixed point called the fulcrum. The bar may be either straight or curved.

In use, a lever has both an effort (or applied) force and a load (resistant force).

2. The 3 Classes of Levers

The class of a lever is determined by the location of the effort force and the load relative to the fulcrum.

The mechanical advantage of a lever is the ratio of the length of the lever on the applied force side of the fulcrum to the length of the lever on the resistance force side of the fulcrum.

First Class Lever In a first-class lever the fulcrum is located in the middle and at some point between the effort

and resistance forces. Common examples of first-class levers include crowbars, scissors, pliers, tin snips and

seesaws. A first-class lever always changes the direction of force (i.e. a downward effort force on the

lever results in an upward movement of the resistance force). Second class lever

the fulcrum is at the end, with the load in the middle e.g. oxygen cylinder trolley,

Third Class Levers In a third class lever the fulcrum is again at the end, but the effort is in the middle

Forceps used in wards3. INCLINED PLANE An inclined plane is an even sloping surface that is higher on one end. The inclined plane makes it easier to move a weight from a lower to higher elevation. A sloping surface, such as a ramp. An inclined plane can be used to alter the effort and distance

involved in doing work, such as lifting loads. The trade-off is that an object must be moved a longer distance than if it was lifted straight up, but less force is needed.You can use this machine to move an object to a lower or higher place.  Inclined planes make the work of moving things easier.  You would need less energy and force to move objects with an inclined plane. 

The mechanical advantage of an inclined plane is equal to the length of the slope divided by the height of the inclined plane. While the inclined plane produces a mechanical advantage, it does so by increasing the distance through which the force must move.

A wagon trail on a steep hill will often traverse back and forth to reduce the slope experienced by a team pulling a heavily loaded wagon.

This same technique is used today in modern freeways which travel winding paths through steep mountain passes.

4. WEDGEThe wedge is a modification of the inclined plane. Wedges are used as either separating or holding devices. A wedge can either be composed of one or two inclined planes. A double wedge can be thought

of as two inclined planes joined together with their sloping surfaces outward. Two inclined planes joined back to back. Wedges are used to split things. A wedge is a simple machine used to push objects

apart. An ax is a wedge that splits wood.

Wedge – Mechanical Advantage The mechanical advantage of a wedge can be found by dividing the length of either slope (S) by

the thickness (T) of the big end. As an example, assume that the length of the slope is 10 inches and the thickness is 4 inches. The mechanical advantage is equal to 10/4 or 2 1/2. As with the inclined plane, the mechanical advantage gained by using a wedge requires a corresponding increase in distance.

5. SCREW A screw is a simple machine used to hold objects together. A screw is an inclined plane wrapped around a shaft or cylinder. The inclined plane allows the screw to move itself when rotated. The screw is also a modified version of the inclined plane. While this may be somewhat difficult to visualize, it may help to think of the threads of the

screw as a type of circular ramp (or inclined plane).

The mechanical advantage of a screw can be calculated by dividing the number of turns per inch.5. Wheel and Axle A wheel and axle is a simple machine made of a rod attached to the center of a wheel. The axle is a rod that goes through the wheel which allows the wheel to turn Gears are a form of wheels and axles You probably have seen a wheel and

axle on scooters, cars, roller skates, and wagons.

When either the wheel or axle turns, the other part also turns. One full revolution of either part causes one full revolution of the other part.

The wrench and screw driver are examples of a wheel and axle, where the screw or bolt is the axle and the handle is the wheel. The tool makes the job easier by changing the amount of the force you exert.

The mechanical advantage of a wheel and axle is the ratio of the radius of the wheel to the radius of the axle.

If the radius of the wheel is five times larger than the radius of the axle. Therefore, the mechanical advantage is 5:1 or 5.

6. PULLEY A pulley is a simple machine with a wheel and axle with a groove around the outside with a

rope. A pulley needs a rope, chain or belt around the groove to make it do work The rope fits around the edge of the wheel. You can use a pulley to move a load up, down or sideways.

A pulley consists of a grooved wheel that turns freely in a frame called a block.

A pulley can be used to simply change the direction of a force or to gain a mechanical advantage, depending on how the pulley is arranged.

A pulley is said to be a fixed pulley if it does not rise or fall with the load being moved. A fixed pulley changes the direction of a force; however, it does not create a mechanical advantage.

A moveable pulley rises and falls with the load that is being moved. A single moveable pulley creates a mechanical advantage; however, it does not change the direction of a force.

The mechanical advantage of a moveable pulley is equal to the number of ropes that support the moveable pulley.

Effort: The force applied to move a load using a simple machine.Resistance: The weight or load that is moved using a simple machine.

CLINICAL IMPLICATIONS OF MACHINES TRACTION AND LIFTINGMachines are widely used in our daily life .in nursing hundreds of procedures are carried out through simple and compound machines. During care of patients we use different types of instruments like forceps, scissors and trolleys. In many articles used in wards, mostly made up of more than one simple machine, patient’s wheel chair, stretchers, beds

We shift the patients in many situations through ramps because the shifting of patients is very difficult through stairs.In surgical tray the chisels, cutting tools and cutting needles are the examples of the wedge.The patients are surgically operated with specific instruments which are the examples of simple machines. The screw drivers are utilized in daily life; it is the example of a wheel and axle.The complicated fractures are fixed using plates which are fixed with nuts and screws Oxygen supplying apparatus and ventilators are made up of more than one simple machine.Orthopedic patients with lower extremities fractures are helped to maintain posture with pulleys and weight as supportive traction.The needle of the syringe is made as the shape of a wedge.Some advanced hospitals use lifts to shift the patients from bed to stretchers and also from one unit to other units.

UNIT NO. 06HEAT

HEAT HEAT is the internal energy in substances. It is the vibration and movement of atoms and molecules within substance. Thermal energy is created in the movement of atoms. Boiling water, burning wood, and rubbing your hands together really fast are all examples of heat energy. Geothermal and passive solar are sources of heat energy, but biomass (a type of chemical energy) can be burned to produce heat energy. The internal motion of the atoms is called heat energy, because moving particles produce heat. It is a measure of the internal energy that has been absorbed or transferred from another

object. Heat Energy is a form of energy that is transferred or absorbed by a difference in temperature. Heat is energy that flows from a higher-temperature object to a lower-temperature object

because of the difference in temperatures. Heat energy causes changes in temperature and phase of any form of matter. The heat energy of an object determines how active its atoms are.

o Two related processes with heat o “Heating” = increasing internal energyo “Cooling” = decreasing internal energy

A hot object is one, whose atoms and molecules are excited and show rapid movement. A cooler object's molecules and atoms will show less movement

SI Unit of Heat: joule (J) Specific Heat – amount of heat needed to raise ONE gram of a material ONE degree Celsius.

The LOWER a material’s specific heat the MORE its temperature rises when energy is added. Heating methods

1. Temperature difference: Energy always moves from higher temperature regions to lower temperature regions

2. Energy-form conversion: Transfer of heat by doing work Metric units

calorie (cal) - energy needed to raise temperature of 1 g of water 1 degree Celsius kilocalorie (kcal, Calorie, Cal) - energy needed to raise temperature of 1 kg of water 1 degree

Celsius English system Unit

British thermal unit (BTU) - energy needed to raise the temperature of 1 lb of water 1 degree Fahrenheit.

Heat is a form of energy, and it is measured in joules. It takes about 4.18 joules or one calorie of heat to change 1 gram of water by 1 Celsius degree.

A unit of heat common in the U.S. is the calorie, which is defined as the amount of heat energy needed to change the temperature of 1 gram of water by 1 Celsius degree (the relationship between calories and joules is that 1 calorie = 4.18 joules).

Heat is pure energy. It does work. It can cause masses to move. Heat can also be transferred or absorbed. Heat can travel from one place to another by 3 ways.

1. Conduction2. Convection3. Radiation

CALORIMETRY

A calorimeter is the experimental apparatus used in a technique known as calorimetry. The kind of heat transfer that occurs within a thermos of iced tea also occurs within a calorimeter.

TEMPERATURETemperature, the degree of “hotness” or “coldness” of an object, is proportional to the average (NOT total) kinetic energy of the atoms or molecules making it up.Temperature is expressed quantitatively by a number that corresponds to the degree of hotness on some chosen scale.The scale most often used world-wide is the Celsius thermometer, where a zero (0) is assigned to the temperature at which water freezes, and 100 is assigned to the temperature at which water boils (at standard atmospheric pressure). Common Temperature ScalesA number of different temperature scales have been devised, two popular choices being the Celsius (formerly, centigrade) and Fahrenheit scales. On the Celsius scale, an ice point of 0 °C (0 degrees Celsius) and a steam point of 100 °C were selected. On the Fahrenheit scale, an ice point of 32 °F (32 degrees Fahrenheit) and a steam point of 212 °F were chosen. The Celsius scale is used worldwide, while the Fahrenheit scale is used mostly to measure body temperature.The temperature of the human body is about 37 °C and 98.6 in Fahrenheit scale. The Kelvin Temperature Scale Kelvin temperature scale was introduced by the Scottish physicist William Thompson (Lord Kelvin, 1824–1907), and in his honor each degree on the scale is called a Kelvin (K). By international agreement, the symbol K is not written with a degree sign (°), nor is the word “degrees” used when quoting temperatures. For example, a temperature of 300 K (not 300 °K) is read as “three hundred Kelvins,” not “three hundred degrees Kelvin.” The Kelvin is the SI base unit for temperature. Kelvin is another way of measuring temperature. It is the SI base unit for temperature.

Scientists use Kelvin to explain the behavior of gases. “Absolute Zero” is measured in Kelvin – which is the

coldest possible temperature Each thermometer has a sensor – a material which is

affected by changes in the environment (such as temperature)

The sensor produces a signal (information about temperature, such as an electrical current) which affects a responder (a pointer, light or other mechanism that uses the signal in some way)

In contrast to high temperatures, there is a definite limit at the opposite end of the scale, called absolute zero.

Temperature is based upon kinetic energy of molecules. The colder something is, the slower the molecules. Eventually, the molecules will slow down SO much, they will essentially stop moving (they will be out of energy, and so they can’t get any colder).

The absolute temperature scale is called the Kelvin scale. Absolute zero is 0 K. The melting point of ice is 273 K, and the boiling point of water is 373 K. There are no negative numbers on the Kelvin scale.

CONVERSION FORMULAS

o Celsius to Fahrenheit

o Fahrenheit to Celsius

o Celsius to Kelvin

F=95C+32°

C=59(F−32° )

K = C + 273

DIFFERENCE BETWEEN HEAT AND TEMPERATURE

HEAT TEMPERATURE The total energy of all the particles in a material.

A measure of the average energy of the particles in a material.

Heat is energy, it can do work. Temperature is a man-made, arbitrary scale indicating which direction heat is flowing

Heat can travel. Temperature can not travel.Heat is the amount of thermal energy in an object because of its moving molecules.

Temperature is a measure of thermal energy or how fast molecules are moving in an object.

To responses of matter to heat, Heat goes mostly into internal kinetic energy

To responses of matter to heat temperature increase within a given phase

If heat goes into the system, means heat is added in a system, it increases kinetic energy of its molecules

If heat goes into the system, temperature rises

if heat leaves the system, means heat is removed from a system, it decreases kinetic energy of its molecules

If the heat leaves the system, temperature declines.

Heat is measured with an instrument called a calorimeter.

Temperature is measured with a thermometer.

Heat is pure energy. It does work. It can cause masses to moveHeat is measured in Joules, Calories and BTU

Temperature can change as heat is added or removed. But temperature is a man made scale.

There are three heat units other than the joule in common useOne kilocalorie (1 kcal) one calorie (1 cal) The British thermal unit (Btu)

Temperature is measured in degree centigrade, Fahrenheit and in Kelvin.There are 3 thermometers, 3 temperature scales. Centigrade or Celsius, Fahrenheit and in Kelvin

Change of state of solid, liquid and gases When heat is applied to the objects or substances or removed from them, the

physical state of the matter can change. If heat is applied to the ice (SOLID STATE) the ice turns into water (liquid) and when water is heated up to 100 C the water changes into⁰ vapors (gaseous) state. In the same way when heat is removed from the different states, the states also change in the same way. This change in states of matter with application and

removal of heat is very beneficial in daily life .Thousands of items are made from metals for daily uses through melting and condensing the metals. We prepare many items for daily uses which are converted from one state to the other states. In example we use water in liquid state for drinking, washing and bathing, but the same water is converted into ice to cool the water for drinking and we also use steam for boiling, and sterilization of instruments in O T. The steam is also used to move a turbine to produce electricity in power houses. We use hot water bottles and iced packs for patients nursing care in hospitals.Heat can travel from one place to another by 3 ways.

1. Conduction2. Convection3. Radiation

Conduction: Heat can travel by conduction. One object can cause cooler objects to heat up. Heat ALWAYS

and ONLY travels from HOT to COLD. So via conduction, a hotter object can transfer the energy to a cooler object.

It happens by contact. One object touches another and the energy of the hotter causes the molecules of the cooler to begin to move faster, that is they have more energy and thus the temperature goes up. Consider a metal spoon in a pan of hot soup. The handle would eventually get hot even though only the bowl of the spoon is in the soup so the atoms of hotter collide with atoms of cooler and transfer their energy.

Conduction is the way heat travels through solids. e.g. we boil water ,cook foods prepare tea or coffee etc.

Convection: The second way that heat travels from one place to another is via convection. Heat travels

through fluids this way. Let us define a fluid… A fluid is anything that flows. Liquids flow. But so do gases…air masses flow in currents, air

flows. When liquids and gases are heated, gain more energy then they become less dense. The

molecules move faster and farther apart. Same mass in larger volume. As a result of less density hot liquids and gases rise.

Removing energy from liquids and gases cools substances. The atoms and molecules have less energy, move slower, cannot escape gravity easily or for as long and so they tend to fall together and sink.

“Fall together” means the molecules and atoms get closer to one another. That is the sample becomes denser. The mass is the same but the volume is smaller. Because the molecules are more dense and because of that it sinks. Colder gases or liquids sink.

e.g. the heat is transferred or removed through this way to cool up or heat up the rooms.

Radiation: It is the way heat can travel through a vacuum, through empty space. Heat travels through nothing on something called an electromagnetic wave. Radiation is the way heat can travel through a vacuum, through empty space.

Heat travels through nothing on something called an electromagnetic wave. This is how heat reaches us from the sun. Radiation, waves, shouldn’t be confused with harmful radiation that is waves of energy

produced when the nucleus of an atom falls apart and radioactivity is released. This is just heat moving through space in something called an electromagnetic wave. Matter can react to EMR in two ways. The heat waves can be absorbed. The energy is taken in

molecules start to move faster and the temperature goes up. E.g. The solar light reaches to us as radiation from sun on the earth. We use different

phototropic instruments in patients care especially in physiotherapy.

Some terms and definitions: A property that changes with temperature is called a thermometric property. The thermocouple is a thermometer used extensively in scientific laboratories. It consists of thin

wires of different metals, welded together at the ends to form two junctions. Thermometer: Mechanical or electrical device for measuring temperature. Early thermometer

was invented by Galileo. Scale: A series of equally measured sections that are marked and numbered for use in

measurement. Celsius Scale: Most commonly used unit of temperature is called a degree. Based on the boiling

and freezing points of water. Boiling Point: The temperature at which water boils. 100 ⁰C at sea level. Freezing Point: The temperature at which water freezes. 0 ⁰C at sea level.

UNIT NO. 7 PRESSURE

Pressure is the ratio of force to the area over which that force is distributed. In other words, pressure is force per unit area applied in a direction perpendicular to the surface of an object.

Pressure is the effect of a force applied to a surface. Pressure is the amount of force acting per unit area. The symbol of pressure is p. Pressure acts in all directions at a point inside a gas. At the surface of a gas, the pressure force acts perpendicular (at right angle) to the surface.

The S I Unit of pressure (the newton per square metre) is called the pascal (Pa) named after the seventeenth-century theologian and scientist Blaise Pascal. A pressure of 1 Pa is small; it approximately equals the pressure exerted by a dollar bill resting flat on a table. Science types more often use kilopascals (1 kPa = 1000 Pa).1 atm= 1.01325 ×105 pascals or 101325 pascals = 14.69595 lbs / in2 =1.01325 bar = 760 torr =1033 gr/cm2

Presently or formerly popular pressure units include the following: atmosphere (atm) manometric units:

o centimeter, inch, and millimeter of mercury (torr)o Height of equivalent column of water, including millimeter (mm H2O), centimeter (cm

H2O), meter, inch, and foot of water customary units:

o kip, ton-force (short), ton-force (long), pound-force, ounce-force, and ), poundal per square inch

o ton-force (short), and ton-force (long) per square inch fsw (feet sea water) used in Under water diving, particularly in connection with diving

pressure exposure and decompression non-SI metric units:

o bar, decibar, millibar msw (metres sea water), used in Underwater diving, particularly in connection

with diving pressure exposure and decompressiono kilogram-force, or kilopond, per square centimeter (technical atmosphere)o gram-force and tonne-force (metric ton-force) per square centimetero barye(dyne)per square centimeter)o kilogram-force and tonne-force per square metero sthene per square meter (pieze)

PRESSURE UNITS

Pre

ssu

re

un

its pascal bar Technical

atmosphereStandard

atmospheretorr Pound per

square inchPa bar at atm Torr psi

1 Pa ≡ 1 N/m2 10−5 1.0197×10−5 9.8692×10−6 7.5006×10−3

1.450377×10−4

1 bar 105 ≡ 106

dyn/cm21.0197 0.98692 750.06 14.50377

1 at 0.980665 ×105

0.980665 ≡ 1 kp/cm2 0.9678411 735.5592 14.22334

1 atm

1.01325 ×105

1.01325 1.0332 ≡ ρₒ ≡ 760 14.69595

1 Torr

133.3224 1.333224×10−3

1.359551×10−3

1.315789×10−3

≈ 1 mmHg 1.933678×10−2

1 psi 6.8948×103 6.8948×10−2 7.03069×10−2 6.8046×10−2 51.71493 ≡ 1 lb/in2

FLUID PRESSUREFluid pressure is the pressure at some point within a fluid, such as water or airFluid pressure occurs in one of two situations:

1. an open condition, called "open channel flow" the ocean, or swimming pool, or The atmosphere.

2. a closed condition, called closed conduits water line, or Gas line.

Pressure in open conditions usually can be approximated as the pressure in "static" or non-moving conditions (even in the ocean where there are waves and currents), because the motions create only negligible changes in the pressure. Such conditions conform with principles of fluid statics.

The pressure at any given point of a non-moving (static) fluid is called the hydrostatic pressure.

Closed bodies of fluid are either "static", when the fluid is not moving, or "dynamic", when the fluid can move as in either a pipe or by compressing an air gap in a closed container. The pressure in closed conditions conforms with the principles of fluid dynamics.

Examples include the pressure in eye ball,s is….. mm Hg and in spinal column fluid is …….mmHg Liquid pressureWhen a person swims under the water, water pressure is felt acting on the person's eardrums. The deeper that person swims, the greater the pressure. The pressure felt is due to the weight of the water above the person. As someone swims deeper, there is more water above you and therefore greater pressure. The pressure a liquid exerts depends on its depth.Liquid pressure also depends on the density of the liquid. If someone was submerged in a liquid more dense than water, the pressure would be correspondingly greater. The pressure due to a liquid in liquid columns of constant density or at a depth within a substance is represented by the following formula: P = ρ g hwhere:

P is liquid pressureg is gravity at the surface of overlaying material

is density of liquidρh is height of liquid column or depth within a substance

Another way of saying this same formula is the following:P = weight density X depthThe average water pressure acting against a dam depends on the average depth of the water and not on the volume of water held back.

Pascal, s LawThe law that deals with pressure in fluids at rest is named for the French philosopher Pascal

(1623-1662). The law states that an increase in pressure applied to any part of a fluid at rest is transmitted undiminished to all parts of the fluid. Pascal, s Law applies to confined fluids in the body, such as the cerebral fluids, enclosed in the subarachnoid space, the urine enclosed in the urinary bladder, the fluid enclosed in the cavities of the eyes and the amniotic fluid surrounding the fetus. Applications other than those in the human body are found in the operation of the hydraulic jack and brake, hydraulically operated sterilizer lids, the air or water mattress and the air ring.

ATMOSPHERIC PRESSURE1. Existence of Atmospheric pressure

According to the kinetic theory of gases, gases consist of molecules which are far apart and in random motion at high speeds.

The gas molecules possess mass and experience the gravitational pull. The result is that gases have weight.

The atmosphere is a thick layer of air that surrounds the Earth. The atmosphere exerts a pressure called atmospheric pressure which is caused by the weight of

the thick layer of air above the Earth's surface. Atmospheric pressure acts on every object on the surface of the earth.Activity to show the existence of Atmospheric Pressure

Boil an empty tin half-filled with water. Cap the tin. Let it cool under running tap water.....the tin will get crumpled as the water cools down. As the steam condenses, the pressure inside the metal tin decreases, the external atmospheric pressure which is Higher, crushes the tin.

Mercury BarometerThe instrument used for measuring atmospheric pressure is called barometer.It is used in meteorological department to predict change in weather. Low pressure on barometer, predicts about the storm or rain and a constant high pressure indicates fair weather.Barometers used for this purpose may be either mercury or aneroid barometer.Because the pressure changes with change in altitude, the height of any top hill or mountain may be measured with change in barometer reading. In aircrafts the altitude is measured with the apparatus called altimeters, are aneroid barometers.

1. A mercury barometer consists of a thick-walled glass tube, which is closed at one end.2. The tube is completely filled with mercury and inverted several times to remove air bubbles.

The tube is then completely filled again with mercury.3. After all air has been removed, the open end of the glass tube is inverted into a container of

mercury.4. The mercury column drops until it reaches a height of about 76cm above the lower surface.

The space between the top of the mercury and the end of the tube should contain no air; it is a complete vacuum.

5. The column of mercury in the tube is supported by the atmospheric pressure and its height depends on the magnitude of the atmospheric pressure.

6. Since the atmospheric pressure at sea level can support a vertical column of mercury 76 cm or 760 mm high, we can, for convenience, express mm Hg as a unit of pressure. 1 Standard atmospheric pressure (1 P atm) = 76 cm Hg or 760 mm Hg (also known as one atmosphere).

POSITIVE PRESSURE AND NEGATIVE PRESSURE

The term positive pressure and negative pressure are not used in classical physics; they are used clinically in reference to pressure above and below that of the normal atmospheric pressure of 760 mmHg.

Positive PressureWhen pressure is kept more than atmospheric pressure, it is known as positive pressure .the

examples include pressure in tyres of the vehicles i.e, 32 psi while atm pressure is 14.7 psi.In an inflated balloon pressure is more than atm pressure. If the pressure goes equal to atm

pressure the balloon will deflate.

Negative pressuresPressures are, in general, positive; there are several situations in which negative pressures may be encountered: When dealing in relative (gauge) pressures. For instance, an absolute pressure of 80 kPa may

be described as a gauge pressure of −21 kPa (i.e., 21 kPa below an atmospheric pressure of 101 kPa).

Negative pressure exists in the transpiration pull of plants, and is used to suction water even higher than the ten meters that it rises in a pure vacuum.

Water sealed suction apparatus creates pressure in the system below than the atmospheric pressure.

Kinetic Theory of GasesThe basic assumption for the kinetic theory of gas is as follows:

Gas is composed of molecules. Gas molecules are continuously in random and independent motion in all directions at high

and different speed. The motion of gas molecules abides by all of the Newton Laws of Motion. All collisions between the gas molecules (i.e. one with another) and the walls of the container

are assumed to be perfectly elastic. Therefore, momentum and kinetic energy are conserved during collision.

The volume of the molecules can be conserved compared to the volume occupied by the gas. The force amongst the gas molecules can be neglected except during collision. The time period of a collision can be neglected when compared with the time interval between

two collisions. Understanding the Gas Laws: Gas theory can be explained by way of the kinetic energy.

When gas molecules collide with the walls of the container and bounce back, a change in momentum occurs in a split second.

The end result of the above momentum is that the walls of the container experience a force. Pressure is defined as the force that acts on a unit surface area. Therefore, all surfaces that are

knocked by air will experience a pressure. This pressure is called gas pressure. One molecule at a slow speed won’t affect but pressure is exerted if all the molecules are

moving at a high speed at the same time to the wall of the container. It exerts pressure.

Understanding Pressure1. Pressure on an area, A is the normal force, F, which is being applied perpendicularly to the

area.2. Pressure on an area, A is expressed as the normal force, F per unit area, A.

P = (F/A)3. The SI unit for pressure is the Pascal, Pa, where 1 Pa = 1 N/m2 (meter square).

4. Pressure is increased:If the force, F applied to a given area, A is increased.If a given force, F is applied to a smaller area, A

5. If a balloon is pressed against by a finger, the balloon will only change its shape a bit. If the balloon is pushed against by a needle with the same force, the balloon will burst. This is because a finger has a larger surface area (A) than a needle. Hence, the needle exerts much pressure than the finger and perforates through the surface of the balloon and making a hole and freeing the air inside the balloon.

GAS PRESSURE

PRESSURE= FORCEAREA

Pressure is a scalar quantity. It has magnitude but no direction

Pressure force acts perpendicular to enclosing surface

Factors Affecting Air or Gas Pressurea. Pressure increases when the density of gas increases.b. Pressure increases when temperature increases due to increase of kinetic energy of molecules.

UNIVERSAL GAS LAW

Pressure in a gas is determined by the number of molecules in a container and their speed. The number of their molecules will depend upon the mass and the volume of the molecules the speed will depend upon the temperature.In equation we can express it as PV= MRTWHERE P= pressure V=volume M=mass of the gas T=temperature R=constant

All three Gas Laws are connected to obtain a Universal Gas Law which is given by PV/T = a constant.That constant is known as the Universal Gas Constant.

PIVIT 1

=P2V 2T 2

This equation represents general gas law which is combination of several gas laws.. These laws known as Boyle’s Law, Charles' Law and Gay- Lussac laws

Boyle's Law: Irish scientist Robert Boyle states that when the temperature of a gas is kept constant the volume varies inversely to the pressure exerted upon it. Or it is stated as that at a constant temperature, the volume of a gas can change with the change in pressure exerted upon it.The volume of a given quantity of a gas varies inversely as the pressure at a constant temperature

V ∝1P

As the pressure increases, the volume decreases As the pressure decreases, the volume increases

This law explains the mechanism of breathing and artificial respiration and the functioning of the respirator.Two other relationships are named for Jacques Charles (1746-1823) a French scientist and his contemporary compatriot Joseph Louis Gay- Lussac (1778-1850) , who worked on gases after Boyle. One relationship states that when the pressure of a gas is kept constant the volume is

proportional to the absolute temperature V ∝t where pressure of a gas is kept constant Or If the pressure is constant, the volume can change with change in temperature V= Kt

The second relationship states that when the volume of the gas is kept constant the pressure is proportional to the absolute temperature.

P ∝t where volume of the gas is kept constant OR If the volume is constant, the pressure can change with change in temperature P= kT * Fluids and gases move from higher pressure to low pressure * Gases are shifted in condensed form, their pressure decreases due to very low temperature but a great mass in less volume e.g, oxygen for hospitals use

THE IMPORTANCE OF PRESSURE APPLICATION IN NURSING

This is a general law of gases that the gases move from higher pressure to lower regions of pressure.

The change in weather environment depends in the change of atmospheric pressure. If the atmospheric pressure of a region on the earth fall, it means that this region can go under a rain, storm or a cyclone, but if the atmospheric pressure remain constant normal it means that the weather is going as normal.

The other important point is to understand the gaseous exchange in lungs. John Dalton stated that the pressure of each gas in a mixture is proportional to its percentage in the mixture. For example if a sample of air at 760 mmHg contains 20.96% oxygen. The partial pressure of the oxygen is equal to 1/5 of 760 or 159.3 mm Hg. This law is known as the Dalton’s law of partial pressure.

Henry’s law states that when the temperature of a gas remains constant, the quantity of a gas that goes into a solution in any given liquid is proportional to the partial pressure of the gas. So we can describe the exchange of gases in human body as under.

The partial pressure exerted by the oxygen is as follows

20.96100

×760=159.3mmHg

The partial pressure exerted by the carbon dioxide is as follows

0.04100

×760=0.3mmHg

Partial pressure expressed in mm Hg during internal & external respiration

UNIT NO.08SOUND AND LIGHT

OVERVIEW: Sound, water and light travel in waves. All three have troughs and crests. Sound is a disturbance of air waves with pitch. Water waves travel in a circle away from the source of disturbance. Light waves travel in a straight line unless they meet an obstacle.Sound

• Sounds are created by Moving molecule in the medium ( Solid, Liquid and Gases)• Sounds are measured by Frequency, Wavelength, Speed, and Amplitude.• Sounds can combine by interference• Sounds can be changed by the Acoustics of the Area or the speed of the source

(Doppler Effect)• Sounds are used in many devices.

Sound Waves1. Sound has both frequency (that we hear directly) and wavelength (demonstrated by simple

experiments).2. The speed of sound is frequency times wavelength.3. In a rigid solid such as ivory which resembles a petrous bone, in its properties, sound travels at

3000 m/sec. in air free water at 10. C the velocity of sound is 1400 m/sec, where in air at 20C IS 343 m/sec. there is an increase in velocity of sound about 0.6 m/sec for each degree rise in temperature centigrade

4. Resonance happens with sound.5. Sound can be reflected, refracted, and absorbed and also shows evidence of interference and

diffraction. 6. A sound wave is a wave of alternating high-pressure and low-pressure regions of air.

Humans are generally capable of hearing sounds between 20 Hz and 20,000KHz. Sounds with frequencies above the range of human hearing are called ultrasound. Sounds with frequencies below the range of human hearing are called infrasound.

TERMS RELATED TO WAVESFrequency = cycles per second. Hz per secVelocity of sound= speed per second in mediumWavelength= it is a distance between the corresponding portions of two waves or the distance travelled in one periodIntensity = it depends on the amount of energy with which the sound wave strikes the tympanic membrane. It is defined as the energy flow across a unit area in a unit time. The greater the energy of the sound, the greater the intensity. As the sound wave spreads from the source, the intensity diminishes.

Pitch= the pitch of the sound is related to the frequency of the sound wave. The greater the frequency

the higher the pitch,

The frequency of a sound wave is called its pitch. High frequency sounds are said to be "high pitched"

or just "high"; low frequency sounds are said to be "low pitched" or just "low".

Amplitude = the extreme displacement of a wave on either side of the position of equilibrium is

known as amplitude.

Diffraction= sound spreads in all directions

Refraction= the light travels in a straight pathway and can change its direction in change of medium

but not diffract like sound.

We hear frequencies of sound as having different pitch. A low frequency sound has a low pitch, like the rumble of a big truck. A high-frequency sound has a high pitch, like a whistle or siren. In speech, women have higher fundamental frequencies than men.

Loudness

Every increase of 20 dB, means the pressure wave is 10 times greater in amplitude. Every increase of 20 dB, means the pressure wave is 10 times greater in amplitude.

Logarithmic scale Linear scaleDecibels (dB) Amplitude0 120 1040 10060 100080 10000100 100000120 1000000

Sensitivity of the ear How we hear the loudness of sound is affected by the frequency of the sound as well as by the

amplitude. The human ear is most sensitive to sounds between 300 and 3,000 Hz. The ear is less sensitive to sounds outside this range. Most of the frequencies that make up speech are between 300 and 3,000 Hz.

How sound is created The human voice is a complex sound that starts in the larynx, a small structure at the top of

your windpipe. The sound that starts in the larynx is changed by passing through openings in the throat and

mouth. Different sounds are made by changing both the vibrations in the larynx and the shape of the

openings. An average human voice has a range of frequencies between 87 and 1060 cycles per second.

The speed of sound

In a rigid solid such as ivory which resembles a petrous bone, in its properties, sound travels at 3000 m/sec. in air free water at 10°C the velocity of sound is 1400 m/sec, where in air at 20°C is 343 m/sec. there is an increase in velocity of sound about 0.6 m/sec for each degree rise in temperature centigrade

The speed of sound in air is 343 meters per second (660 miles per hour) at one atmosphere of pressure and room temperature (20°C).

An object is subsonic when it is moving slower than sound. We use the term supersonic to describe motion at speeds faster than the speed of sound. A shock wave forms where the wave fronts pile up. The pressure change across the shock wave is what causes a very loud sound known as a sonic

boom.

Standing waves and resonance

Spaces enclosed by boundaries can create resonance with sound waves. The closed end of a pipe is a closed boundary. An open boundary makes an antinode in the standing wave. Sounds of different frequencies are made by standing waves. A particular sound is selected by designing the length of a vibrating system to be resonant at

the desired frequency. Sound waves and boundaries

Like other waves, sound waves can be reflected by surfaces and refracted as they pass from one material to another.

Sound waves reflect from hard surfaces.

Soft materials can absorb sound waves.

Recording sound1. A common way to record sound starts with a microphone. A microphone transforms a sound

wave into an electrical signal with the same pattern of oscillation. 2. A single frequency by itself does not have much meaning. The meaning comes from patterns in

many frequencies together. A sonogram is a special kind of graph

that shows how loud sound is at different frequencies.

Every person’s sonogram is different, even when saying the same word.

Music The pitch of a sound is how high or low we hear its frequency. Though pitch and frequency

usually mean the same thing, the way we hear a pitch can be affected by the sounds we heard before and after.

Rhythm is a regular time pattern in a sound. Music is a combination of sound and rhythm that we find pleasant. Most of the music you listen to is created from a pattern of frequencies called a musical scale.

Consonance, dissonance, and beats Harmony is the study of how sounds work together to create effects desired by the composer. When we hear more than one frequency of sound and the combination sounds good, we call it

consonance. When the combination sounds bad or unsettling, we call it dissonance.

Consonance and dissonance are related to beats. When frequencies are far enough apart that there are no beats, we get consonance. When frequencies are too close together, we hear beats that are the cause of dissonance. Beats occur when two frequencies are close, but not exactly the same.

What Is an Ultrasound?

Ultrasound is a procedure that uses high-frequency sound waves to view internal organs and produce images of the human body. In the Ultrasound we mainly use ultrasound frequencies of 1, 2 and 3 MHz.The human ear cannot hear the sound waves used in an ultrasound. Ultrasound is: Noninvasive procedure, which means it does not penetrate the skin or body openings, and Diagnostic, which means it is used to determine what disease or condition is present The technical term for ultrasound imaging is sonography. Ultrasound technology was originally developed as sonar to track submarines during World War I. It was first used medically in the 1950s and is considered very safe. The original ultrasound scanners produced still images, but modern scanners produce moving pictures, which are easier to interpret.

How does Ultrasound work?

Ultrasound imaging uses the principles of sonar developed for ships at sea. As sound passes through the body it produces echoes, which can identify distance, size and shape of objects inside.

During the ultrasound examination, a machine called a transducer is used to view the target organ and produce pictures for study. The transducer emits sound and detects the returning echoes when it is placed on or over the body part being studied.

When the emitted sound encounters a border between two tissues that conduct sound differently, some of the sound waves bounce back to the transducer, creating an echo.

The echoes are analyzed by a computer in the ultrasound machine and transformed into moving pictures of the organ or tissue being examined.

Ultrasound waves pass easily through fluids and soft tissues, making the procedure especially useful for examining fluid-filled organs such as the uterus in pregnancy, as well as the gallbladder, and soft organs like the liver.

Ultrasound waves are unable to penetrate bone or gas, so ultrasound is of limited use for examining regions surrounded by bone, or areas that contain gas or air. Even so, ultrasound has been used to examine most parts of the body.

Transducer

• A device that converts one form of energy to another •  The hand-held portion of the ultrasound imaging machine, which sends sound waves into

the body, and records echoes produced by the waves.– Piezoelectric crystal: a crystal that produces (+) and (-) electrical charges when it

contracts or expands1. Crystal of quartz, barium titanate, lead zirconate, or titanate housed within

transducer– Reverse (indirect) piezoelectric effect: occurs when an alternating current is passed

through a crystal resulting in contraction & expansion of the crystal1. ultrasound is produced through the reverse piezoelectric effect2. Vibration of crystal results in high-frequency sound waves

– Fresnal zone (near field) – area of the ultrasound beam on the transducer used for therapeutic purposes

The benefits and limitations of ultrasound Ultrasound is a noninvasive imaging technique. It is a painless procedure.

Ultrasound is widely available, low cost and easy to use. Because it does not use radiation, the side effects of radiation are not an issue. So, ultrasound

is the preferred technique for monitoring pregnant women and their unborn children. Real-time images are generated by ultrasound, so it is a good tool for

guiding invasive procedures like needle biopsies. Ultrasound can display the movement and actual function of the body's organs and blood

vessels. There are no known harmful effects of standard ultrasound imaging. The main limitation of ultrasound imaging is that it does not reflect clearly from bone or air.

Therefore, other imaging techniques are preferred for areas such as the lungs and the bones.

LIGHT

• Light is a type of radiation; it is a type of wave that travels through space.• Light waves are fundamentally different from many other waves that travel only through material

media (sound or water waves). • Light waves require NO material medium to travel from place to place.• The wave speed of all types of light in a vacuum is called the speed of light, c

c = 300,000 km/sec

Wave speed = frequency x wavelengthSpeed of light (radio waves) = c = 3x 108m/sec

Distance = speed x timex103 Hz (AM radio frequencies)x106 Hz (FM radio frequencies)

Creating Electromagnetic Waves• All matter is made up of atoms.• Atoms are, in turn, made up of smaller particles: protons, electrons, and neutrons.• Two of the elementary particles that make up atoms possess a property described as

electrical charge. • The charges on each are equal and opposite.

electron: - charge proton: + charge

Electrical force:• is a universal force (every charged particle affects every other charged particle)• may be attractive or repulsive force• is always directed along the line connecting two charges• depends on the product of the two charges

• depends on the distance between the two charges squared (obeys the “inverse square rule”)• Today, physicists describe electric forces in terms of an electrical field produced by the

presence of electrical charge.• An electric field extends outward in all directions from any positively charged particle. • If a charged particle moves, its electric field changes.• The resulting disturbance travels through space as a wave.

MAGNETIC FIELDS• If an electric field changes with time (let’s say the source charge wiggles), then a magnetic

field is created, coupled to the time-variant electric field.• Magnetic fields influence behavior of magnetized objects.• Earth’s magnetic field causes compass needles to point N• bar magnets and electromagnets

ELECTROMAGNETISMElectric and magnetic fields do not exist as independent entities. They are different aspects of a single phenomenon:Electromagnetism (EMR)

Together, they constitute an electromagnetic wave that carries energy and information from one part of the universe to another.

FREQUENCY AND ENERGY Light waves carry energy (E) across space.

• Light is created by the motion of charged particles.• Matter is made up of atoms, which are in turn made up of charged particles.• Motions of these charged particles create light.

– Not just the light we detect with our eyes, but at all wavelengths (or frequencies).Electromagnetic Spectrum

Properties of Light:

Reflection Refraction Dispersion Diffraction Interference

Reflection and Refraction• An isolated light beam travels in a straight line.• Light can change directions under certain conditions:– Reflection from a surface, E.G. mirrors, objects– Refraction (or bending of a ray of light) as the ray travels from one transparent medium to another.

• A fish in water tank• light through a piece of glass

Dispersion:• Electromagnetic waves interact with the charged particles in matter and travel more slowly in

transparent media than in a vacuum.• The change in speed of the light wave causes the wave to refract.• Since the speed of an EM wave in a medium changes with wavelength, the amount of refraction

depends on the wavelength.• This effect is called dispersion.

Visible Light• Prism will separate light into its components• Composed of 7 hues (Roy G. Biv), known as its spectrum– Red (~ 700 nm or 7000 Å) – Orange ,Yellow, Green, Blue, Indigo, Violet (~ 400 nm or 4000 Å) • Color determined by its frequency (or, equivalently, its wavelength)

Visible Spectrum

Diffraction• Diffraction is the bending of a wave as it passes through a hole or around an obstacle. – If light consists of parallel rays, they would travel through a small pinhole and make a small, bright

spot on a nearby screen.

SHARP- EDGED SHADPWFUZZY SHADOW

Effect cannot be explained by ray model of light. Diffraction of Waves

• Actually observe a spot larger than the pinhole and varying in brightness. – The pinhole somehow affects the light that passes through it.• Diffraction is proportional to the ratio of wavelength to width of gap.

– The longer the wavelength and/or the smaller the gap, the greater the angle through which the wave is diffracted.

Fuzzy spectrumInterference and Superposition

• What happens if two waves run into each other?• Waves can interact and combine with each other, resulting in a composite form.• Interference is the interaction of the two waves.– reinforcing interaction = constructive interference– canceling interaction = destructive interference • Superposition is the method used to model the composite form of the resulting wave.

Interference of Waves Interference: ability of two or more waves to reinforce or cancel each other.

Constructive interference occurs when two wave motions reinforce each other, resulting in

a wave of greater amplitude.

Destructive interference occurs when two waves exactly cancel, so that no net motion remains.

UNIT NO. 9

ELECTRICITY• Matter is made up of atoms• Atoms are made of nucleons (called protons and neutrons) and electrons• Protons have a positive charge, neutrons have no charge, and electrons have a negative charge

and can move freely.• The charges of protons and electrons are equal and opposite• Electrons move in and out of fixed pathways around the nucleus

Red Orange Yellow Green Blue Violet

• Changing the number of electrons in a particular type of atom creates an ion of that atom• Electrons in the outer rings or shells of atoms are bound more loosely to the nucleus• Such electrons tend to break free from the nucleus and wander around amongst other nearby

atoms. Such electrons are called free electrons • Electrons can move from atom to atom. When an electron moves to a different atom, it causes

another electron to have to move. When electrons move quickly from one atom to another electrons creates an electric current and it is called flow of electrons or electricity.

• A charge is a measure of the extra positive or negative particles that an object has.• Two kinds: positive and negative (terms coined by Benjamin Franklin)• Movement of the electrons physically from one place to another is slow. Transfer of the energy

from one electron to another happens fast. • Materials with large numbers of free electrons are called electrical conductors. They conduct

electrical current.

ELECTRICITYElectrons can move from atom to atom. When an electron moves to a different atom, it causes another electron to have to move. When electrons move quickly from one atom to another is it called Electricity

It is all about electrons, which are the fundamental cause of electricity The electricity is divided into two categories

• Natural electricity • Artificial or human generated electricity

Natural electricity It consists of Static Electricity and lightening in clouds (thunder storms electricity) Some animals also have the ability to produce an electric shock Static Electricity • Static electricity is the charge that stays on an object.• It involves electrons that are moved from one place to another, usually by rubbing or brushing• When you rub a glass rod with silk, the charge that is left on the glass was called positive. If you

rub a hard rubber rod with silk, the charge left on the rod was called negative. Lightening in clouds (thunder storms electricity)• The electric current is produced in between the different layers of clouds due to friction in air and

vapors • This current is produced in a large amount (from some Megawatts to gaga watts) but it is unable

to utilize for human needs. Artificial or human generated electricity The electricity is produced all over the world for human utilization. Basically it consists of two types • Direct current: it is utilized mostly in vehicles to produce capacitors ignition and battery

charging .it provides low current on slow rate.rpm• Alternate current: for home, offices and industrial use. it provides high voltage current on fast

rate.rpm i.e 50 to 60 Hz per second• The flow of electricity is somewhat analogous to the flow of water. The electromotive force

(Voltage) is comparable to the pressure exerted by a pump.• The current (ampere) which gives the number of electron passing a given point in a unit of time it

is 6.25x1018 electrons per second at a given point.

• The resistance (ohm) is due to the nature of the conductor and its length and cross section area is comparable to the friction between the water molecules and the walls of the tube through which the water flows.

• Electron flow takes place only when there is a difference between the parts of the circuit. • Watt is the product of volts and amperes .in example

Electric power = Volts x amperes 3600 = 100 volts x 36 amperes

• Electric energy is the product of electric power and time . The common unit of electric energy are the watt-hour and kilo watt –hour.

Current/ Electricity It involves the flow of electrons in a conductor The steady flow of electricity is called an electric current/ Electricity. A current will move along a wire or a path called a circuit.Circuit means to “go around.”Current = ConductionCircuits: a wire or a path through which electric current flows is called a circuit.It consists of two types series circuit is & series circuit

A series circuit is a circuit that has only one path for the current. A parallel circuit has more than one path for current to travel. Lights in our homes are wired in parallel circuits.

Conductor Conductors A conductor is a material that current can pass through easily ,e.g. metals and humans are both conductors.Electrolytes:Both negative and positive charges can move .e.g solution of H2SO4 in a battery SemiconductorsIn-between conductors and insulators in their ability to conduct electricityConductivity can be greatly enhanced by adding small amounts of other elementsInsulators do not allow electricity to flow through easily. Rubber, glass, and plastic are all good insulators.An insulator is a material that current cannot pass through it easily, like plastic.Resistor

• A resistor is a material that resists, but doesn’t stop the flow of current.

Electric Cell• An electric cell supplies energy to move charges through a circuit, like a battery.

NATURE OF ELECTRICITY The flow of electric current through electrolytes can change the basic chemical properties of the

compounds. If we pass current through water in presence of electrolytes the current can break down the water

molecules into simple hydrogen and oxygen gases The movement of electron through any living material can change its properties. In living

organisms the electrical charge can change the electrolyte balance which is very much important for life. If the amount of electron (current) exceeds above from 240 volts, is fatal for human life and can seize the heart conduction.

If this electric current is used in a safe and organized way. It is beneficial for us in thousands of daily utilities.

We can use electricity for home, offices and industrial uses. In medical field instruments are operated through electricity like monitors, ventilators, heaters air

conditioners, operation theatres equipments, nebulizers, suction apparatus etc. Defibrillator is used to restore the heart movement Electro convulsive therapy is used to treat seriously suffering mental disorders patients electrocardiography and electroencephalography are the tests carried out through electric

impulses PRECAUTIONS DURING THE USE OF ELECTRICITY When someone uses electric equipments in home or hospital, some precautions always keep in mind to prevent from electric shock hazards • The electric supply should match with the demand of the home or unit.• Always use equipments made by a certified and approved company.• The wiring of the equipments should be unbroken and free of tear from any point.• The switch should match to the pin plug of the equipment• The flow of electric current should be matched to the equipment s, requirement.• The pin plug should be safe and spark free.• Electric instruments should be checked from any expert person for the efficiency and accuracy of

function• The continuously operated equipments should be shut off in a day to prevent from heat if possible.

In hospitals it is impossible to stop ventilators, so cooling system of the ward should be properly managed.

• The electric switches and oxygen supplying apparatus should be kept on a distance to protect of explosion due to any sparking.

• Never use open wires (without pin switch) into a plug. It can cause of electric shock.• During defibrillation of a patient keep away from the body and bed of the patient• Pacemaker applied patient should avoid to touch any type of current

TERMS

• Inertia is property of matter by which it resists change in its state of rest or in its direction of motion.

• PHYSICS is the branch of science, which deals with the study of properties of matter, energy and their mutual relationship.

• Kilowatt-hour is a unit of energy equivalent to the energy produced when power of 1 kilowatt is expended for 1 hour.

• Ultrasonic Means sound waves of high frequency (20,000 Cycles per second and higher) inaudible to human ear.

• Velocity is the rate of change of position of a body in a given time in a definite direction.

• Voltage is the electromotive force in electricity.• Mechanics is the study of motion and the physical affect which influence motion.• Electromagnetism is the study of electromagnetism phenomena and mutual relationship

between them.• Atomic and molecular physics is the study of atoms and molecules of material things.• Study of physics enables the nurses to understand the basic fundamental units of

measurement, necessary for the accuracy of fluids and medicines during nursing practice.• There are 3 fundamental SI units for LENGTH, MASS, and TIME. • The first standardized system of measurement: the “Metric” system Developed in France in

1791 Established in 1960, at the 11th General Conference on Weights and Measures.• Unit: measure of the quantity that is defined to be exactly 1• Prefix: modifier that allows us to express multiples or fractions of a base unit• National Bureau of Standards is International Bureau of Weight and Measures in Paris • Physical quantity: A quantity that can be measured by instrument, clearly defined and has

proper units is called physical quantity. • Physical quantities are classified as fundamental and derived quantities• Fundamental units  The physical quantity which does not depend on any other physical

quantity• The base units:A unit of measurement that can be determined by taking one measurement

without having to combine with any other measurement• The Seven Base SI UnitsQuantity are meter, kilogram, Kelvin, second, mole, candela and

ampere• meter :The currently accepted definition of meter is the length of path travelled by light in

vacuum in 1/299,792,458th second.• Kilogram: Kilogram is the fundamental unit of mass. • Second: Second is the fundamental unit of time.• Coulomb: Coulomb is the fundamental unit of charge.• Candela: Candela is the fundamental unit of luminous intensity.• Kelvin: Kelvin is the fundamental unit of temperature.• Mole: Mole is the fundamental unit of quantity of matter.• DERIVED UNITS:The units that can be obtained from fundamental units are called derived

units.• One Kilogram=1000 grams= 2.2046223 pounds• One pound =16 ounce = 453.5924 grams• Motion is a change in position of an object with respect to time.• Linear motion : when a body moves either in a straight line or along a curved path, then we

say that it is executing linear motion.• Rotatory motion : A body is said to be in rotatory motion when it stays at one place and turns

round and round about an axis.• Oscillatory motion : a body is said to be in oscillatory motion when it swings to and fro about a

mean position. Example: the pendulum of a clock, the swing etc.• Dynamics : In dynamics we discuss the motion of bodies under the action of forces.• Kinematics : it deals with the study of motion of bodies without any reference to the cause of

motion.• Force is an action /agent that can change motion of a body.• Force is an action /agent that can change state of rest of a body.• Centripetal force is the inward force exerted on an object to keep it moving in a curved path. • Centrifugal force is the outward force exerted on the object that makes it want to fly off into

space• Inertia is a term used to measure the ability of an object to resist a change in its state of

motion. • Newton’s 1st Law – An object at rest will stay at rest, and an object in motion will remain in

motion at constant velocity, unless acted upon by an unbalanced force.

• Newton’s 2nd Law – Force equals mass times acceleration.• Newton’s 3rd Law – For every action there is an equal and opposite reaction.• Scalars are quantities which are described by a magnitude only.• Vectors are quantities which are described by both a magnitude and a direction.• Distance: length between two points in a straight line or length moved through a definite path.• Displacement: Distance moved in a definite direction (vector quantity).

In physics, the word position refers to the location of an object at one instant.• A position is always specified relative to an origin. • The net change in position relative to the origin is called displacement.• Units of speed could be: km/h, m/s, mi/h, ft/s• Average speed is the average of all instantaneous speeds; found simply by a total distance/total

time ratio• Velocity is the distance travelled in a specific direction.• The unit of FORCE is in Newton (N).• The ACCELERATION due to gravity is given a special letter, g. and it is = 9.8 m/s2 • Units of speed could be: km/h, m/s, mi/h, ft/s• Unit of Distance: SI unit: metre (m) Other common units: kilometre (km), metres,centimetre

(cm)• Unit of Displacement: SI unit: metre (m) Other common units: kilometre (km), centimetre

(cm)• Unit of Acceleration: SI unit: m/s2 • Friction is a force between two surfaces that are sliding, or trying to slide across one another,

for example when you try to push a toy car along the floor.• Friction always works in the direction opposite from the direction the object is moving, or

trying to move. It always slows a moving object down.• Cause of Friction: the microscopic roughness between surfaces…like two gears locking

together.• High friction (lots of friction) – will slow something down• Low friction (not much friction) – will keep things moving • Types of friction ,Static ,Sliding, Rolling and Fluid• Dry friction: occurs when non smooth (non ideal) surfaces of two solids are in contact under a

condition of sliding or a tendency to slide.• Sliding• Friction resulting when pushing or pulling an object over a surface.• Fluid friction is Resistance from a “liquid” or air.• The main disadvantage of friction is that it produces heat in various parts of machines. In this

way   some useful energy is wasted as heat energy.• The ability to grasp objects in hands is due to the friction provided by the ridges of the fingers

and hands.• Gravity is defined as the force which gives freely falling objects on or near the surface of the

earth with acceleration.• On the earth its value is 9.8m/sec2.

• Center of gravity of a body is a point where total weight of the body is concentrated.• Center of gravity of a circle is at its center.• Gravity exercises are sometimes prescribed for patients with circulatory disorders of the lower

extremities. • The change in position aids in improving circulation of the blood. • A diagnostic test ESR erythrocyte sedimentation rate is done on the base of gravity • A body is said to be in equilibrium if it is at rest or moving with uniform velocity.

Torque is the tendency of a force to rotate an object about an axis fulcrum, or pivot.• Motion in which an entire object moves is called translation. • Motion in which an object spins is called rotation.• The point or line about which an object turns is its center of rotation.

• Torque is created when the line of action of a force does not pass through the center of rotation.

• Energy can be defined as the capacity for doing work or ability to do work.• The faster an object moves, the more kinetic energy it has.• The greater the mass of a moving object, the more kinetic energy it has.• Kinetic energy depends on both mass and velocity.• Stored energy is potential energy ,it can be changed into Kinetic Energy• Potential energy that is dependent on height is called gravitational potential energy.• Chemical energy is the energy stored in the bonds of atoms and molecules.• light energy that travels in waves; have electrical and magnetic properties• Electromagnetic Energy is also carried by X-rays, radio waves, and laser light.• High power rays are harmful to human and animals • Light is the movement of photons• Light travels in straight lines and in transverse waves. • Light transmits ENERGY.• Magnetic energy is the attraction of objects made of iron• Thermal energy is the internal energy in substances-the vibration and movement of atoms and

molecules within substance.• Heat energy causes changes in temperature and phase of any form of matter.• Mechanical energy is also the total amount of kinetic and potential energy in a system. • Sounds are caused by vibrations and travels in longitudinal waves. • Electrical energy is caused by the movement of electrons.• The generation or use of electric power over a period of time expressed in kilowatt-hours

(kWh), megawatt-hours (NM) or gigawatt-hours (GWh).• Nuclear energy is the energy stored in the nucleus of an atom.• When atomic nuclei join together it is known as nuclear fusion. • When atomic nuclei are split apart it is known as nuclear fission.• Kg of Uranium produces energy through nuclear fission equal to the burning of 25 lac Kgs of

Coal in an atomic reactor.• Energy is always changing from one kind to another. The total energy of an object never

changes.• Work is the transfer of energy through motion. • Efficiency of a device is defined as the percentage of the energy input that is transformed into

useful energy. • Power is defined as the rate of doing work. • A machine is a device that helps make work easier to perform by accomplishing one or more

functions.• Simple Machines can be put together in different ways to make complex machinery• A lever is a rigid bar that rotates around a fixed point called the fulcrum.• In a first-class lever the fulcrum is located in the middle and at some point between the effort

and resistance forces.• In Second class lever, the fulcrum is located at the end, with the load in the middle• In a third class lever the fulcrum is again at the end, but the effort is in the middle Forceps used

in wards• An inclined plane is an even sloping surface that is higher on one end.• The wedge is a modification of the inclined plane. Wedges are used as either separating or

holding devices. • A screw is a simple machine used to hold objects together.• A wheel and axle is a simple machine made of a rod attached to the center of a wheel.• A pulley is a simple machine with a wheel and axle with a groove around the outside with a

rope.• Effort: The force applied to move a load using a simple machine.• Resistance: The weight or load that is moved using a simple machine.

• The screw drivers are utilized in daily life; it is the example of a wheel and axle.• Orthopedic patients with lower extremities fractures are helped to maintain posture with

pulleys and weight as supportive traction.• The needle of the syringe is made as the shape of a wedge.• It is a measure of the internal energy that has been absorbed or transferred from another

object.• Heat Energy is a form of energy that is transferred or absorbed by a difference in temperature.• Heat is energy that flows from a higher-temperature object to a lower-temperature object

because of the difference in temperatures.• “Heating” = increasing internal energy• “Cooling” = decreasing internal energy• calorie (cal) - energy needed to raise temperature of 1 g of water 1 degree Celsius• kilocalorie (kcal, Calorie, Cal) - energy needed to raise temperature of 1 kg of water 1 degree

Celsius• British thermal unit (BTU) - energy needed to raise the temperature of 1 lb of water 1 degree

Fahrenheit.• the relationship between calories and joules is that 1 calorie = 4.18 joules• A calorimeter is the experimental apparatus used in a technique known as calorimetry. • Temperature, the degree of “hotness” or “coldness” of an object, is proportional to the average

(NOT total) kinetic energy of the atoms or molecules making it up.• By international agreement, the symbol K is not written with a degree sign (°), nor is the word

“degrees” used when quoting temperatures.• “Absolute Zero” is measured in Kelvin – which is the coldest possible temperature• Heat travels through fluids from one place to another is via convection. • Conduction is the way heat travels through solids. It is the way heat can travel through a

vacuum, through empty space.• A property that changes with temperature is called a thermometric property. • The thermocouple is a thermometer used extensively in scientific laboratories. It consists of

thin wires of different metals, welded together at the ends to form two junctions.• Thermometer: Mechanical or electrical device for measuring temperature. Early thermometer

was invented by Galileo.• Scale: A series of equally measured sections that are marked and numbered for use in

measurement.• Celsius Scale: Most commonly used unit of temperature is called a degree. Based on the

boiling and freezing points of water.• Boiling Point: The temperature at which water boils. 100 ⁰C at sea level.• Freezing Point: The temperature at which water freezes. 0 ⁰C at sea level. • Pressure is the ratio of force to the area over which that force is distributed• The S I Unit of pressure (the newton per square metre) is called the pascal• 1 atm= 1.01325 ×105 pascals or 101325 pascals • 1 atm = 14.69595 lbs / in2 =1.01325 bar = 760 torr =1033 gr/cm2

• Fluid pressure is the pressure at some point within a fluid, such as water or air• The pressure at any given point of a non-moving (static) fluid is called the hydrostatic

pressure.• The pressure a liquid exerts depends on depth and density of the liquid• The average water pressure acting against a dam depends on the average depth of the water and

not on the volume of water held back.• Pascal, s Law states that an increase in pressure applied to any part of a fluid at rest is

transmitted undiminished to all parts of the fluid. • The atmosphere exerts a pressure called atmospheric pressure which is caused by the weight

of the thick layer of air above the Earth's surface.• Atmospheric pressure acts on every object on the surface of the earth.• The instrument used for measuring atmospheric pressure is called barometer.

• 1 Standard atmospheric pressure (1 P atm) = 76 cm Hg or 760 mm Hg (also known as one atmosphere).

• When pressure is kept more than atmospheric pressure, it is known as positive pressure• When pressure is kept less than atmospheric pressure, it is known as negaitive pressure• According to Boyle,s law :As the pressure increases, the volume decreases and as the pressure

decreases, the volume increases• Charles , law ;One relationship states that when the pressure of a gas is kept constant the

volume is proportional to the absolute temperature • Gay- Lussac ,s law states that when the volume of the gas is kept constant the pressure is

proportional to the absolute temperature. P ∝t • Fluids and gases move from higher pressure to low pressure • Gases are shifted in condensed form, their pressure decreases due to very low temperature but a

great mass in less volume e.g, oxygen for hospitals use • The law of the partial pressure is known as the Dalton’s law of partial pressure.• Henry’s law states that when the temperature of a gas remains constant, the quantity of a gas

that goes into a solution in any given liquid is proportional to the partial pressure of the gas.• Protons have a positive charge, neutrons have no charge, and electrons have a negative charge

and can move freely.• Static electricity is the charge that stays on an object.• The flow of electricity is somewhat analogous to the flow of water. The electromotive force

(Voltage) is comparable to the pressure exerted by a pump.• The current (ampere) which gives the number of electron passing a given point in a unit of

time it is 6.25x1018 electrons per second at a given point. • The resistance (ohm) is due to the nature of the conductor and its length and cross section area

is comparable to the friction between the water molecules and the walls of the tube through which the water flows.

• Electron flow takes place only when there is a difference between the parts of the circuit. • Watt is the product of volts and amperes .in example • Electric power = Volts x amperes • 3600 = 100 volts x 36 amperes• Electric energy is the product of electric power and time . The common unit of electric energy

are the watt-hour and kilo watt –hour.• A series circuit is a circuit that has only one path for the current.• A parallel circuit has more than one path for current to travel.• A conductor is a material that current can pass through easily ,e.g. metals and humans are both

conductors.• Electrolytes:Both negative and positive charges can move .e.g solution of H2SO4 in a battery • Semiconductors• In-between conductors and insulators in their ability to conduct electricity• Insulators do not allow electricity to flow through easily. Rubber, glass, and plastic are all

good insulators.• Resistor: A resistor is a material that resists, but doesn’t stop the flow of current.• Electric Cell: An electric cell supplies energy to move charges through a circuit, like a battery.• In living organisms the electrical charge can change the electrolyte balance which is very much

important for life.• Defibrillator is used to restore the heart movement• The electric switches and oxygen supplying apparatus should be kept on a distance to protect

of explosion due to any sparking.• During defibrillation of a patient keep away from the body and bed of the patient• Pacemaker applied patient should avoid to touch any type of current• Transducer: The hand-held portion of the ultrasound imaging machine, which sends sound

waves into the body, and records echoes produced by the waves.• Sound, water and light travel in waves.

• Sound is a disturbance of air waves with pitch. • Sounds are created by Moving molecule in the medium ( Solid, Liquid and Gases)• Sounds are measured by Frequency, Wavelength, Speed, and Amplitude.• The speed of sound is frequency times wavelength.• In a rigid solid such as ivory which resembles a petrous bone, in its properties, sound travels at

3000 m/sec. in air free water at 10. C the velocity of sound is 1400 m/sec, where in air at 20C IS 343 m/sec. there is an increase in velocity of sound about 0.6 m/sec for each degree rise in temperature centigrade

• Resonance happens with sound.• Sound can be reflected, refracted, and absorbed and also shows evidence of interference and

diffraction. • Humans are generally capable of hearing sounds between 20 Hz and 20,000KHz. • Sounds with frequencies above the range of human hearing are called ultrasound.• Sounds with frequencies below the range of human hearing are called infrasound.• Amplitude = the extreme displacement of a wave on either side of the position of equilibrium

is known as amplitude.• Diffraction= sound spreads in all directions • Refraction= the light travels in a straight pathway and can change its direction in change of

medium but not diffract like sound.• The human voice is a complex sound that starts in the larynx, a small structure at the top of

your windpipe. • The sound that starts in the larynx is changed by passing through openings in the throat and

mouth. • An average human voice has a range of frequencies between 87 and 1060 cycles per second.• We use the term supersonic to describe motion at speeds faster than the speed of sound.• Spaces enclosed by boundaries can create resonance with sound waves.• Music is a combination of sound and rhythm that we find pleasant.• In the Ultrasound we mainly use ultrasound frequencies of 1, 2 and 3 MHz.• Light waves require NO material medium to travel from place to place.• An isolated light beam travels in a straight line. Light can change directions under certain

conditions.• Refraction (or bending of a ray of light) as the ray travels from one transparent medium to

another.• Light can reflect from a surface like mirrors, objects, known as reflection.• A solar light beam can be divided into different colours by a prism, it is called dispersion.• Diffraction is the bending of a wave as it passes through a hole or around an obstacle.