# AP Physics Chapter 1 Study Guide

## Concepts of Motion and Mathematical Background

Welcome to the AP Physics Chapter 1 Study Guide. This chapter is an introduction to the study of motion and some background knowledge of mathematics.

## Motion Diagrams

There are four main types of motion that will be covered in this class. Straight-line motion, projectile motion, circular motion, and rotational motion.

 Straight-line Motion Projectile Motion Circular Motion Rotational Motion Combination

## Creating a Motion Diagram

This is four frames from a movie. The time between frames is constant. For example, most television is filmed in 30 frames per second. So the time between frames is 1/30 th of a second.

However this would be tedious to use film for motion diagrams. So if we make a motion diagram pictured below, that would be easier. It is emphasised that the time between images is a constant.

If you are anything like me in drawing this would also be to tedious. So what we do is think of the cars as a particle, or point. This is usually the center of mass of the object. The motion diagram now looks like the image below.

Some other motion diagrams to discuss. Draw a particle motion diagram for each of the following diagrams.

Which car is going faster, A or B?

Give an example of a object that could be moving for each of the following motion diagrams.

## Position and Time

We need to have an easier way of finding position than the above diagram.

But, will this work for another situation.

Then on a none flat surface the situation changes.

But, how does time come into play for the motion diagrams?

Instead of putting just numbers on the motion diagrams we could put time in seconds or minutes or any other time appropriate to the situation.

Describe a situtation that the above motion diagram shows.

## Displacement

Displacement is the change in position of an object, calculated by taking the final position minus the initial position.

To find the displacement above you take the final position (150 ft) then subtract the initial position (50 ft) from the final to get a displacement of 100 ft.

This displacement will be negative, because 0 ft minus 50 ft is a negative 50 ft.

## Velocity

Speed is a the rate of motion, or equivalently the rate of change in position, often expressed as distance d traveled per unit of time t. Speed is a scalar, because it has no direction.

Velocity is defined as the rate of change of displacement. It is a vector quantity; both speed and direction are required to define velocity.

## SI Units

 Factor Prefix Symbol yotta- Y zetta- Z exa- E peta- P tera- T giga- G mega- M kilo- k hecto- h deka- da deci- d centi- c milli- m micro- µ nano- n pico- p femto- f atto- a zepto- z yocto- y

## Vectors

Scalar is a physical quantity that has magnitude but no direction.

Vector is a physical quantity that has both magnitude and a direction.

Vector Addition - when you add vectors you must use trigonometry and triangles to add the vectors.

Sample Vector Practice in Class

Pictoral representation of vectors.

An example of the velocity of a ball thrown in the air.