1. Acceleration

2. What is Acceleration?
A measure of the change in velocity during a period of time
An object accelerates when:
its velocity changes (increasing/decreasing speed or changing direction)
So changing speed or direction

3. Another Way of Saying Acceleration
The rate at which velocity changes

4. Examples of Acceleration
On a roller coaster – as it changes speed and direction
In a car when you hit the gas
In a car when you slam on the brakes!

5. Can You Feel Acceleration?
Yes! You can feel acceleration in a car push you forward, backward, or side to side.
This is due to the rate of change in velocity (acceleration)

6. What If? YES! This is a change in velocity!
When a car slows down is it accelerating?
YES! This is a change in velocity!

7. Representing Acceleration
Just like velocity, acceleration has a direction
This is represented by an arrow

8. Speeding Up
Final velocity longer arrow
Acceleration points forwards

9. Slowing Down Final velocity shorter arrow
Acceleration points backwards

10. Changing Direction
Following the velocity arrows, we see that the change in direction is toward the inside of the curve

11. Average Acceleration vf Final Velocity vi Initial Velocity t Time
a Acceleration

12. Average Acceleration Problem
A bicyclist started from rest along a straight path. After 2.0s his speed was 2.0m/s. After 5.0s his speed was 8.0m/s. What was his average acceleration?
Initial Speed?
Final Speed?
Total Time?

13. Average Acceleration Problem
A bicyclist started from rest along a straight path. After 2.0s his speed was 2.0m/s. After 5.0s his speed was 8.0m/s. What was his average acceleration?
2.0 m/s2

14. Why m/s2 Because acceleration is the meters per second… per second
So we square the seconds instead of saying m/s*s

15. How to do it! How to do acceleration problems!
Khan Academy Acceleration Problem

16. Practice
Textbook pg. 33 #1-4