1. Bellringer 8/30 
What is the difference between speed and velocity?

2. Today’s Target…
I can use observations and appropriate tools to document the position and motion of objects. This means I can make observations about how an object’s motion changes.

3. Acceleration

4. REVIEW What is motion? How do we know an object is in motion?
How do we measure motion?
What is the difference between speed and velocity?
How do we find speed?

5. Acceleration
Consider this: a car is stopped at a red light, when the light changes the driver gently steps on the accelerator and the car speeds up or accelerates
In everyday language acceleration means “the process of speeding up”

6. Acceleration Acceleration is the rate at which velocity changes
Remember that velocity is speed and direction
Acceleration is
increasing speed
decreasing speed
changing direction

7. Increasing Speed
Any time the speed of an object increases it experiences acceleration
What are some examples of acceleration?
A car that moves from a stopped position
Runners taking off

8. Decreasing Speed Decreasing speed is also acceleration
Called negative acceleration or deceleration
What are some examples of deceleration?
A ball rolling to a stop
A car coming to a red light
An airplane landing

9. Changing Direction
Remember that velocity involves both speed and DIRECTION, so a change in direction is also acceleration
You may think that a car traveling at constant speed does not accelerate, but actually it does because it will change directions!

10. Changing Direction Examples: Race car drivers rounding a turn
Any circular motion
The seats on a Ferris wheel

11. Did you get it?
How is it possible for a car to be accelerating if its speed is steady at 65 mph?

12. Determining Acceleration
Speed
Time
60 km/h 0s
62 km/h 1s
64 km/h 2s
66 km/h 3s

13. Determining Acceleration
Speed
Time
12 m/s 0s
8 m/s 1s
4 m/s 2s
0 m/s 3s