Question

Simple Pendulums

“Periodic motion” is motion that repeats itself. One example of “periodic motion” is a simple pendulum. The mass of a simple pendulum is all at its bottom. For a simple pendulum, the time it takes for one complete swing (a.k.a. the “period”of the pendulum) depends only on the length of the string:

Period = 2π times square root of (length / g).

If the length is measured in centimeters and the pendulum is on Earth where g = 980 cm/s² then this formula gives the period in seconds.  The value of π is 3.14

Show your work on each of the following three exercises.

A) Confirm that the period and length measured ( time 29.92 second, length 25 cm, period=20 ) are consistent with the formula.​  

B) Calculate the period you would expect for a swing whose length is 2 meters (200 centimeters). You probably remember swinging on a swing like that. Does your answer seem about right?

C) Calculate the length a simple pendulum would need to have in order for its period to be 3 seconds. That’s a pretty long period for a pendulum so it should turn out to be a pretty long pendulum

Answer 1