1. Circular Motion

3. The period of the ball is the time to orbit once.
The frequency is the number of orbits in one second.
The speed is the distance traveled in one period

4. Radius

5. Centripetal Acceleration
Acceleration means a change in speed or in direction.
Has the ball accelerated in the collision?

6. Has the ball accelerated as it orbits?

7. Direction of Acceleration.
Centripetal acceleration is always towards the centre of the circle

8. What two things affect the size of the centripetal acceleration
What two things affect the size of the centripetal acceleration? (remember a change in direction means acceleration)

9. Both balls have the same radius
(1) Speed
Both balls have the same radius
Which ball accelerates most?
SLOW
FAST

10. Both balls have the same speed
(2) Radius
Both balls have the same speed
Which ball accelerates most?
BIG RADIUS
SMALL RADIUS

11. Centripetal Acceleration
As speed increases, centripetal acceleration
As radius increases, centripetal acceleration
increases
decreases

12. The equation for centripetal acceleration is……………

13. Centripetal Force
When something moves in a circle, it accelerates towards the centre.
This requires a
Its called centripetal force and is always towards the
FORCE
CENTRE

14. When acceleration is zero, you feel no sideways forcev
Speeding up
When you accelerate forward you imagine a force backward a v
Slowing down
When you accelerate backward you imagine a force forward a v

15. Going Around the Bend you are taking a DVD back to the shop.
Its on the dashboard.
What happens when you turn a corner?

16. velocity
centripetal force

17. Imaginary force a
Centripetal force

18. Centripetal Force is any force that keeps things moving in a circle
Centripetal Force is any force that keeps things moving in a circle. What provides the centripetal force for……
A ball on a string
Tension
A mouse on a spinning turntable
Friction

19. Centripetal Force Equation

20. What happens if the centripetal force is removed?
What direction will the car slide when it hits the ice?
ICE

21. Which law does this illustrate?
Newton’s 1st Law.
An object will have constant velocity unless a net force acts on it.

22. Centripetal force

23. Which side of the road should you spectate from?

24. Excellence Examples
1.0 kg
The maximum breaking strain of the string is 25 N. The radius is 1.0m. Calculate the minimum period before the string snaps.
Explain how the ball can be moving at constant speed even though there is an unbalanced force on it