1. Circular Motion What is acceleration?
How can we keep a ball rolling in a circle or a battery-operated car moving in a circle?
Take a look...

2. To the lab tables…
Experiment with the tape and marble until you can move the marble in a circle with constant speed. What is the direction of the acceleration? What is the direction of the net force?
Make a prediction about what will happen when you lift the tape while the marble is moving. Then test your prediction.

3. So where is the acceleration?

4. Centripetal Acceleration, ac
Period: Length of time needed for object to make one complete revolution. T = 1/f where f is frequency.

5. The formula…

6. Examples:

7. Let’s Work an Example…
A 13-g stopper is attached to a 0.93-m string. When swung in a circle, the apparatus completes one revolution in 1.18 seconds. Find the tension force the string exerts on the stopper.

8. What’s ac ?
ac = 4π2r/T2
r = 0.93m
T = 1.18s
ac = 26.3 m/s2

9. Albert is swinging a yo-yo around his head. The yo-yo has a mass of 0
Albert is swinging a yo-yo around his head. The yo-yo has a mass of kg and the length of string from his hand to the yo-yo is 0.75 m. The yo-yo makes one revolution in 1.2 s. What is the magnitude of the force exerted by the string on the yo-yo?
A = 20.5 m/s2 and F=0.58 N

10. Exit slip:
In circular motion, what aspects of velocity and acceleration vectors are similar? What aspects are different?
Describe speed, velocity, and acceleration in uniform circular motion.
Why do you slide toward the outside of a car when you make a turn?