Chapter 1-3 Outline

Chapter 1

Introduction, Measurement, Estimating

Two branches of Physics:

Classical Modern

Motion (Mechanics), Fluids, Head, Sound, Light, Electricity and

Magnetism

Relativity, Matter, Nuclear, Particles

1-1 Nature of Science• Observations

– Includes designing and carrying out experiments– Often have to use your imagination, as not every detail is always

observed• Theories

– These are the other half of scientific process– Often derive from observations– Are formed and corrected through observations and experiments

• Testing– Theories can be tested and supported, but they are never “proven”– This is due to an inexactness of measurement and lack of ability to test

every possible theory, thus theories often change over time– Theories which are more general and explain more are accepted– The simpler theory is accepted

1-2 Physics and its Relation to Other fields

• Physics has evolved from philosophy; physics is involved in most sciences

1-3 Models, Theories, and Laws

• Model– analogy or imagery to explain phenomena

• Theory– broader than a model (also testable)

• Principle/Law– Laws are principles that have been found to

be true in many cases

1-4 Measurement and Uncertainty: Significant Figures

• Precision = consistency; Accuracy = correctness

• Significant figures = non-zero numbers

• Scientific Notation = M x 10n

1-5 Units, Standards, and the SI System

• Measurements need units

• Units need a standard, which defines what the unit is

• Length = m, Time = s, Mass = kg

• There are 7 base units: m, s, kg, A, K, mol, cd (we don’t use candela)

1-6 Converting Units

• Use factor-label

1-7 Order of Magnitude: Rapid Estimating

• This is how I want you to estimate answers to see if they are reasonable (using Sci Not)

1-8 Dimensional Analysis

• Very important! Can help you determine what the equation should be

Chapter 2

Describing Motion: Kinematics in One Dimension

Chapter 2: 1-D Kinematics

• Mechanics = the study of the motion of objects (force and energy)– Kinematics-HOW objects move– Dynamics-WHY objects move

• Translational Motion = motion without rotation

• Particle Model = we are only concerned how the object would move if it were a particle (i.e., it cannot rotate)

2-1 Reference Frames and Displacement

• Reference frame = what the motion is relative to

• Coordinate axis = same as in math class

• Position = displacement from origin

• Displacement = distance that has a direction and is relative to its starting point

2-2 through 2-4: Speed, Velocity, and Acceleration

• Speed is the rate at which you travel• Average speed is the change in distance over

the change in time• Velocity is speed with a direction• Average velocity is displacement over time• Instantaneous velocity is the velocity as the time

interval approaches zero (infinitesimally small)• Acceleration is the rate at which the velocity

changes

2-5 Constant Acceleration• Leads to the Kinematics equations

• We use x for distance/position/displacement (technically position)

2-6 Solving Problems

• Demonstrate #14, 15, 20, 30, 31 (Final three students will try on their own)

2-7 Falling Objects

• All fall at the same rate, 10 m/s2

2-8 Graphical Analysis of Linear Motion

• Same rules that we learned last year (slope of x-t is v, curvature is a; slope of v-t is a, area is displacement)

• This year we will include acceleration-time graphs (a-t graph is the slope of the v-t graph, area under an a-t graph is the change in velocity)

• Also, all graphs must be rounded off when changing between regions-you may not have a region that has an infinite slope or dotted lines

Practice Problems

• Problems: Pages 39-44

• Demonstrate: #14, 15, 20, 30, and 31

• Homework: Problems 21, 25, 39 (window in helicopter), 56, 84, and 85

Chapter 3

Kinematics in Two Dimensions; Vectors

Chapter 3: Kinematics in 2-D; Vectors

• Projectile Motion: Objects projected outward near the surface of the Earth

• Vectors are needed to use as a tool

3-1 Vectors and Scalars

• Vector = has magnitude and direction

• Scalar = no direction associated with them

• Magnitude is represented by length, direction tip

• Vectors are bold in the text

3-2 Addition of Vectors-Graphical Methods

• If vectors are collinear, you may add them algebraically (one direction positive, opposite negative)

• If vectors are at angles to one another, must use another method

• Resultant is the net result when adding (multiplying) vectors

• Tail-to-tip method is a way to add vectors

3-3 Subtraction of Vectors and Multiplication of a Vector by a Scalar

• Subtracting is like adding a negative

• To make a vector “negative,” reverse the direction

• When multiplying by a scalar, change the magnitude of the vector only

3-4 Adding Vectors by Components

• Components = parts of a vector that, when added together, make the original vector

• Resolving = making a vector into its components

• We use the x, y, and z components– x = rcos– y = rsin

3-5 Projectile Motion

• Projectile Motion = motion in 2-D

• Motion in one direction is independent of motion in the other direction

3-6 Solving Problems Involving Projectile Motion

• Make an info box

• Modified kinematics equations

x y

d0

df

vo

vf

a

t

3-7 Projectile Motion is Parabolic

• Parametric Equations: x = v0xt

y = v0y – ½ gt2

3-8 Relative Velocity

Velocities may be changed from one reference frame to another if you know how fast the frames are moving relative to one another

Practice Problems

• Problems: Pages 65-68

• Demonstrate: #31

• Homework: Problems #17, 18, 35, 30, and 41