1. Acceleration

2. Definition Any change in velocity is acceleration What are the possible causes of acceleration? Speeding up Slowing down Changing direction

3. Position-Time Graphs for Acceleration

4. Average Acceleration Change in velocity divided by the time taken Acceleration is a vector with + or – signs showing direction Units are usually m/s/s or m/s 2

5. A car accelerates along a straight road from rest to 75 km/hr in 5.0 sec. What is the average acceleration?

6. If the velocity of an object is zero, does this mean the acceleration is zero? If acceleration is zero, does this mean that velocity is zero?

7. A car is moving at 15 m/s and puts on his brakes. It takes 5.0 s to slow to 5 m/s, what is the acceleration?

8. Velocity vs. Time Graphs Slope of velocity time graph is acceleration If line is curved, can find the instantaneous acceleration by finding the slope of a tangent to the curve at that point

9. a = 10m/s – 10m/s 5s – 0s = 0m/s 2

10. a = 50m/s – 0m/s 5s – 0s = 10 m/s 2

11. Distance Traveled The area under a velocity time graph gives you the distance traveled How far did the car travel?