TURBO TAKS
Week 6
Lesson 1: Body Systems
Lesson 2: Heat Transfer & Waves
Lesson 3: Energy & Electricity
Lesson 4: Motion, Forces, & Physics Equations
Lesson 1: Body Systems
The Human Body must also maintain homeostasis (a balance). The organs of the body work together in organ systems to perform specific functions.
Organ systems are often connected and work together to allow the body to function.
Integumentary: Skin, hair, nails: Protects, prevents infection, temperature control
Skeletal Support and protection of organs.
Muscular Uses bones as simple machines to exert force on the body to create movement.
Nervous Control system of the body. Works with other systems to maintain homeostasis.
Endocrine Secretes hormones that circulate in the blood stream and tell other systems what to do.
Reproductive: produces gametes in ovaries and testis.
Circulatory: transports oxygen and nutrients to cells and removes wastes.
Respiratory Brings O2 to circulatory system and removes CO2 (gas exchange!).
Immune Fights infection Helper T-cells and macrophages turn on the immune response and start attacking invaders.
Digestive: breaks down food and absorbs nutrients
Excretory Takes waste from the blood stream for removal from the body.
Lesson 2: Heat Transfer and Waves
Heat Transfers• Heat moves from hot to cold.
• Example: When you put your hand on a lab table it feels cold because the heat in your hand is leaving your body and transferring down, into the table. Not the other way around.
– Heat from the 25oC block is sinking into the 10oC block
– Heat does not rise, hot air rises.
Conduction
Conduction transfers from one substance to another by direct contact of
molecules.
THINK: Solids
Example: When you touch a hot stove!
ConvectionConvection transfers heat through moving currents in fluids (gases or liquids). Convection cannot occur in
solids, because solids can’t move.
• THINK: Liquids and Gases
Hot liquids (and gases) are less dense
and rise, causing convection currents.
These currents transfer heat
throughout the liquid (or gas).
Heat Source
Hot Liquid Rises
coolerliquidfalls
coolerliquidfalls
Much of the weather on earth comes from convection currents.
The sun warms air at the surface of the earth. Warm air
rises, causing winds. When the air cools it falls back to the
ground.
Hot air rises
Cold air is pulled in from the sides causing wind.
wind windwarm
ground
sunshine
Much of the weather on earth comes from convection currents. The sun warms air at the surface of the earth. Warm air rises, causing winds. When the air cools it falls back to the ground
Radiation
• Examples: •The sun warming your face.•Warmth you feel sitting
close to a campfire.
Heat (thermal energy) in the form of electromagnetic radiation from a light
source.
Lets PracticeName the type of heat transfer:
1.Boiling water in a pot.
20ºC 20ºC
30ºC 40ºC
A
BD
C
CONVECTION
3. McDonalds keeping french fries warm under a heat lamp.
CONDUCTION
RADIATION
2. Your feet burning on concrete in the Summer time.
4. Which letter represents a possible heat transfer?
D(Always hot .
cold)
Waves
A wave is any disturbance that transmits energy through matter or space
Types of Waves
1.
2.
Types of Waves
• 1. Compression/ Longitudinal wave• Produced by moving a slinky spring back and
forth.
• Example: Sound
Types of Waves• 2. Transverse Wave
• Produced by waving
a rope or other medium
up and down
• Example: Light wave, or a ripple in a pond
Parts of a Transverse Wave
Characteristics of All Waves
• Wavelength- distance from a point in a wave to the next point on the next wave in the same phase
• Frequency- the number of times that a repeated event occurs per second• For sound, High pitch
= high frequency
• V = f λ
(Velocity = frequency x wavelength)
Short Wavelength = High Frequency
Long Wavelength = Low Frequency
Wave Properties• Reflection
• When waves bounce off a hard boundary.
• The sound waves are bouncing off the tank. (i.e.- mirror, echo)
• Refraction• The bending of light as it passes from one medium into another. (i.e.- lenses)
Wave Properties• Diffraction
• Occurs when a wave bends around a corner.
• Interference• A wave
interaction that occurs when two or more waves overlap.
Click screen when ready…
Wave Properties• Resonance
• Occurs when one object vibrates because of another object’s vibrations.
• Common in tuning forks and other musical instruments
• Example: Earhearing
• Body of guitar vibrates
because of it’s strings
vibration. Click screen when ready…
Make sure sound is turned down.
Lets Practice• Answer with: Reflection, Refraction,
Diffraction, Interference, or Resonance. 1. Lenses 2. Using a mirror 3. Water waves
passing through an opening.
4. When the primary colors of light combine to form white light
5. When singing near a piano, the keys can start to sound.
REFRACTION REFLECTION DIFFRACTION
INTERFERENCE RESONANCE
Lesson 3: Energy and Electricity
Energy
• Energy is the ability to cause motion or forces; the units of energy are joules (J).
Potential Energy• 1. Gravitational Potential Energy (in Joules, J) is
stored energy, because an object is above the ground.
• More height = more Potential Energy. It has the potential to cause motion and forces.
• Gravitational Potential Energy= mass x gravity x height
Ep = mgh
Potential energy equals mass times gravity times height.
Potential Energy
(in Joules)
mass (in kilograms)
height (in meters)
acceleration due to gravity (9.8 m/s2 )
Potential Energy• The acceleration due to gravity we
experience on Earth is 9.8 m/s2. In space, gravity is 0 m/s2.
• Potential Energy Practice: PE=mgh
Don’t forget to use the given constants and formulas!
Ex: How much potential energy does a 4 kg object have that is 5 meters off the ground?
Ep = mghEp = (4)(10)(5)
= (40)(5)= 200 Joules
takes 5,000 J of energy)
m = 4 kg h = 5 m g = 10 m/s2
Ep = ?
m =h =g =Ep =
Kinetic Energy
• Kinetic Energy (in Joules, J) is the energy of motion. Moving objects have kinetic energy.
• Kinetic Energy= ½ mass x velocity2
• Mass is measured in kilograms (kg) and velocity is measured in meters/second (m/s).
Ek = (½)mv2
Kinetic energy equals one-half Times mass times velocity squared.
Kinetic Energy
(in Joules)
mass (in kilograms)
velocity (in m/s)
Energy Transfers
• Work (in Joules, J) is how forces change energy. • Work=Force x Distance
• Power (in Watts, W) is how fast work is done.• Power = Work
Time
W = FdWork (in Joules)
Force (in Newtons)
Distance (in meters)
P = W/TPower(in Watts)
Work (in Joules)
Time (in seconds)
• Energy can be transferred from one type to another.
x100out
in
WEff
W
Efficiency
• Efficiency is the percentage of energy retained (not lost) in an energy transfer.
Efficiency CalculationWork In: Work Out:How much energy you tried to
give to the object thru an energy transfer or work.
How much energy is actually gained by the object (how much it got out).
Here work is done on the object, pulling it up the ramp. This is the total energy that you tried to give the
object.
Work put in 240 J.
F in =
30 N10
kg
Before
After
10 kg
D = 8m
The object only got out 200 J.
x100
x100
200 Jx100
240 J .83 x 100
= 83%
out
in
p
WEff
W
EEff
W
Win=Fd= 30(8)=240 J
Wout=Epgained
=mgh =10(9.8)2 =98(2) = 196J
196
.82 x 100
=82%
Types of Energy
• Thermal Energy—Heat energy. A product of most other forms of energy.
• Mechanical Energy—Any kind of Kinetic (moving) or Potential (height) Energy.
• Chemical Energy—Stored in chemical bonds. Includes energy in food, plants, and batteries (produce electricity
by combining chemicals).
• Electrical Energy—Energy of moving electrons: lightening, electricity.
• Radiant Energy—Light energy from light bulbs or the sun (renewable solar energy).
• Nuclear Energy—Energy from nuclear reactions (radiation): makes huge amounts of energy, but also long-term, radioactive waste like power plants.
Lets PracticeWORD BANK
a) Kinetic Energy
b)Potential Energy
c)Energy
d)Height
e)Joules
Match with the terms to the right:
1. The units for energy.
2. The ability to create forces or motion.
3. Energy because of an object’s motion.
4. Energy because of an object’s position above the ground due to gravity.
5. Vertical distance above the ground.
Electricity• Moving of electrons through conductors.
The path must be closed, or electrons cannot move.
Electrical Circuits
• Series Circuit• Provides a single
conducting pathway without junctions.
• Parallel Circuit• When two or more components of
a circuit are connected across junctions, providing separate pathways for the current.
Notice how the
lines are “parallel”!
Which type of circuit would you rather have for your Christmas lights?Parallel, so that if one light burns out, the current can still reach
the other bulbs.
Assuming the chart contains all energy transformations in the Earth system, how much solar radiationgoes toward evaporating water?F 40,000 terajoulesG 92,410 terajoulesH 121,410 terajoulesJ 133,410 terajoules
Subtract all the energy expenditures from the total amount reaching Earth.
173,410 – 52,000- 81,000 – 370 – 40 = 40,000
Let’s
Practice
with
Energy!
Lesson 4: Motion, Forces, and Physics Equations
Speed and Velocity• Speed is the distance an object travels per second. • Velocity includes the speed of an object and the direction of its motion.
• They share a formula on your equation sheet.
d
s t
Speed equals the distanced traveleddivided by the time it took to move that
distance.
Distance travelled (in meters)Time
(in seconds)
Speed (in
meter/sec)
v =dt
Measuring SpeedTo measure speed you must determine the
distance traveled and the elapsed time.
25m5m/s
5sec
DS
T
Acceleration
a =
Acceleration equal change of velocity divided by change of time.
Change of Velocity
(in meters/sec)
Change of Time
(in seconds)
Acceleration
(in m/s2)
, so, final initialfinal initial
V VV V V a
T
a =
a =
ΔV
ΔT
An object accelerates when it changes speed OR changes direction!
If acceleration is unknown use acceleration due to gravity out of the constants box on the
formula chart!
Acceleration is how fast you change velocity OR how much the velocity changed in a certain amount of time.
Solving for Acceleration1. Calculate initial velocity
8m
1sec8m/s
f
final
DV
TV
4m
1sec4m/s
i
initial
DV
TV
2
8 4
24
2m/s2
f i
initial
V Va
T
V
Accelerates for 2 seconds4 m
Measure Vf
(Final Velocity)
8 m
Measure Vi
(Initial Velocity)
Measure ΔT (Time it took to
Accelerate)
3. Determine the change in time.
2. Calculate final velocity 4. Plug into acceleration equation.
So ΔT = 2 sec
MOMENTUM
• Momentum is how hard it is to stop something and is a product of an object’s mass and its velocity. Momentum is increased if either the mass or velocity is increased.
Momentum equals mass times velocity.
Momentum
The canon ball has a smaller mass and a larger velocity. The canon has a larger mass and a smaller velocity. However, since the system started with a net momentum of zero, the momentums of the objects afterwards must be equal and opposite to cancel each other out, or = 0.
Pcanon = Pcanon ball
Forces
• A force is a push or pull that one body exerts on another. Force is measured in Newtons (N).
• Forces can add and subtract.
15 N 65 N
10 kg
Total Net Force = +65 -15= 50 N
Right is positive.Left is negative.
Newton’s Laws of Motion:
1. An object in motion will stay in motion unless a force acts upon it. (Law of Inertia). If an object is at rest, it will stay at rest until acted upon. *Why we need seatbelts.
2. Force = mass x acceleration*Why a bowling ball does not go as fast as a ping pong ball when the same force is applied.
3. For every action there is an equal and opposite reaction.*Why a rocket goes up when gasses push down.
InertiaInertia is the tendency to not change motion, and is dependent only on the object’s mass (measured in kilograms).
- Newton’s First Law.
Object’s with more mass have more inertia and are harder to push.
Object’s with less mass have less inertia and are easier to push.
Frequent Equations from the Formula Sheet
Solving Physics Problems:1. Identify what is being asked and
underline or highlight it.
2. Find the appropriate formula and write it down in your test booklet.
3. Plug in the known information (WRITE IT OUT).
4. Solve for the unknown.
Lets Practice the Steps Together…• What is the approximate difference in
gravitational potential energy of a 2kg object 3m off the ground and a 2kg object 1m off the ground?
• F) 19J
• G) 39 J
• H) 59 J
• J) 79 J
First SituationPE=mghPE=(2)(9.8)(3)PE= 58.8 J
Second SituationPE=mghPE=(2)(9.8)(1)PE= 19.6 J
Difference Between=58.8 – 19.6 = 39.2 J or approximately 39J = G
gravitational potential energy
The illustration above shows a student about to throw a ball while standing on a skateboard. Which illustration below correctly shows the skateboard’s direction of motion after the student releases the ball?
Let’s Practice!
A B C D
skateboard’s direction of motion
• A cyclist moves at a constant speed of 5 m/s. If the cyclist does not accelerate during the next 20 seconds, he will travel —
• A 0 m
• B 4 m
• C 50 m
• D 100 m
They are asking for distance and giving us speed and time.
S=d/t5=d/20
(Multiply by 20 on each side of the equal sign.)
20 x 5= 100m = D
• How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N?
• F 300 J
• G 750 J
• H 1,000 J
• J 15,000 J
work
W=FdW= (20)(15)W= 300 J = F
Watch out for extra information!
Levers
Which lever arrangement requires the least effort force to raise a 500 N resistance?
A mechanic used a hydraulic lift to raise a
12,054 N car 1.89 m above the floor of a
garage. It took 4.75 s to raise the car. What
was the power output of the lift?
• A) 489 W
• B) 1815 W
• C) 4796 W
• D) 30,294 W
This is a two part calculation.You’re looking for Power, but must have work before you can solve (P=w/t)
1. Calculate work:w=fdw=(12054)(1.89)w=22,782.06 J
2. Calculate power:P=w/tp=(22,782.06)
(4.75)P=4796.22 WWe know it’s a force because it’s
measured in Newtons!
• A ball moving at 30 m/s has a momentum of 15 kg·m/s. The mass of the ball is —
• A 45 kg
• B 15 kg
• C 2.0 kg
• D 0.5 kg
momentum
Momentum = mass x velocityP=mv15=m(30)Divide by thirty on both sides.15/30= 0.5 kg = D
