1. Pendulums

2. Definition Simple Pendulum – Massive object, called a bob, suspended by a string or light rod of length, l. Periodic Motion – Motions that repeat in a regular cycle

3. Terms to Describe Pendulums Period (T) – time needed for an object to repeat one complete cycle of motion Amplitude (A) – maximum distance that the object moves from equilibrium (start)

4. What affects the period of a pendulum? The only variable that affects the period of a pendulum is the length of the string. l

5. How do I find the Period? T = Period l = length of string g = acceleration due to gravity, 9.81 m/s 2 = 3.14

6. Uses of Pendulum? Timekeeping

7. Uses of Pendulum? Determination of Gravity (9.81 m/s 2 )

8. Uses of Pendulum? Rotation of the Earth But How?

9. Foucault’s Pendulum

10. Jean Bernard Leon Foucault –Set up a pendulum and noticed that it shifted places as it swung! –http://en.wikipedia.org/wiki/Image:Fouca ult-anim.gifhttp://en.wikipedia.org/wiki/Image:Fouca ult-anim.gif –It shifted around 270 o in 24 hours! –Proving that the earth was rotating around on its axis.

11. Example A pendulum is made on Earth with a 40 g mass and a 2 m long string. What will be the period of the pendulum????

12. On Your Own A pendulum on Earth has a length of 5 m. What is the period of this pendulum?

13. Challenge George went to Planet Z and made a pendulum. His pendulum was 4 meters long and George found that it had a period of 4.012 seconds per swing. What is the acceleration due to gravity on Planet Z?