1. Kinematics Average Acceleration

2. Variables In addition to the variables previously used to calculate average velocity (v avg ), we add one more: a- acceleration (m/s 2 ) a avg - average acceleration

3. Solving for acceleration Acceleration can be found 2 ways: Graphically- read from a Velocity vs. Time graph Mathematically- found using an equation

4. Graphically Imagine a velocity vs time graph: Consider the SLOPE of this line.

5. Graphically The slope is Δv/Δt = (10m/s) / (5s) Look at the UNITS of the slope…

6. Graphically Same units as acceleration.

7. Graphically The SLOPE of a VELOCITY vs. TIME graph represents the ACCELERATION of the moving object.

8. Mathematically Formula: The formula looks like the slope of the velocity vs. time graph: That is where it comes from.

9. Example A shuttle bus slows down with an average acceleration of -1.8 m/s 2. How long does it take the bus to slow from 9.0 m/s to a complete stop.

10. Example A shuttle bus slows down with an average acceleration of -1.8 m/s 2. How long does it take the bus to slow from 9.0 m/s to a complete stop. Givens: a= -1.8 m/s 2 v i = 9.0 m/sv f = 0 m/s (implied) Unknown: t=?

11. Example A shuttle bus slows down with an average acceleration of -1.8 m/s 2. How long does it take the bus to slow from 9.0 m/s to a complete stop. Givens: a= -1.8 m/s 2 v i = 9.0 m/sv f = 0 m/s (implied) Unknown: t=? Formula:

12. Example A shuttle bus slows down with an average acceleration of -1.8 m/s 2. How long does it take the bus to slow from 9.0 m/s to a complete stop. Givens: a= -1.8 m/s 2 v i = 9.0 m/sv f = 0 m/s (implied) Unknown: t=? Formula:

13. Practice Page 49, Practice B. ALL units will be in meters, seconds, and m/s.