1. Acceleration and Motion
Chapter 3 Notes
Acceleration and Motion

2. Chapter Objectives
Relate velocity and acceleration to the motion of objects.
Draw and interpret velocity-time graphs.
Determine mathematical relationships among position, velocity, acceleration, and time.
Solve constant-acceleration problems using graphs and mathematical relationships.
Define free fall.
Solve free fall problems.

3. Velocity-Time Graphs
What does the slope of a velocity-time graph indicate?

4. Change in Velocity!! Acceleration is any change in velocity
Example: What are the three controls in a vehicle that cause it to accelerate?

5. Instantaneous Acceleration

6. Positive and Negative Acceleration

7. Interpret Velocity-Time Graphs

8. Position with Constant Acceleration
We know that

9. Example Problem
The v-t graph below shows the motion of an airplane. Find the displacement of the airplane at Δt = 1.0 s and at Δt = 2.0 s.

10. Determining Motion Mathematically
Kinematic equations
These equations must be memorized!

11. Problem-Solving Strategy
Draw a picture.
List variables.
Determine proper equation.
Replace variables in equation with known values and their units!
Solve.
Check to make sure units are correct.

12. Example Problem
An automobile starts at rest and speeds up at 3.5 m/s2 after the traffic light turns green. How far will it have gone when it is traveling at 25 m/s?

13. Example Problem
You are driving a car, traveling at a constant velocity of 25 m/s, when you see a child suddenly run onto the road. It takes 0.45 s for you to react and apply the brakes. As a result, the car slows with a steady acceleration of 8.5 m/s2 and comes to a stop. What is the total distance that the car moves before it stops?

14. Free Fall
The motion of a body when air resistance is negligible and the action can be considered due to gravity alone.
Acceleration due to gravity (g)
g=9.80 m/s2

15. Example Problem
A student drops a ball from a window 3.5 m above the sidewalk. How fast is it moving when it hits the sidewalk?

16. Example Problem
You decide to flip a coin to determine whether to do your physics or English homework first. The coin is flipped straight up. If the coin reaches a high point of 0.25 m above where you released it, what was its initial speed after you let go of the coin?