http://www.ck12.org Chapter 10. Simple Harmonic Motion
Pendulum Lab (PhET Simulation)Explore More
- Why doesn’t the period of a pendulum depend on the mass of the pendulum weight? Shouldn’t a heavier
weight feel a stronger force of gravity? - The pendulum of a small clock is 1.553 cm long. How many times does it go back and forth before the second
hand goes forward one second? - On the moon, how long must a pendulum be if the period of one cycle is one second? The acceleration of
gravity on the moon is one sixth that of Earth.
Answers to Selected Problems1..
2. 4 times
3. 0.04 m
Investigation
We have explored two examples of simple harmonic motion: the pendulum and the mass-spring system in the
previous lesson. The purpose of this investigation is to get you to notice the connections between the two systems.
Your task: Match the period of the pendulum system with that of the spring system. You are only allowed to change
the mass involved in the spring system. Consider the effective length of the pendulum to be fixed at 2m because
that is the distance between the center of mass and the pivot. The spring constant(13.5N/m) is also fixed. You may
use any relationships you have learned about to help you. You should view the charts to check whether you have
succeeded.
Instructions: To alter the mass, simply click on the ’select’ tool in the menu, and select the mass. Then use the tab
at the bottom of your screen to change the density or dimensions of the block to get the mass that you want.
To view chart legend, click on Settings and you can plot velocity or position of the pendulum or mass on the spring.