The Period of a Pendulum

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Purpose

To study how the period of a pendulum depends on:

1. the mass of the pendulum bob;
2. the amplitude (angle) of swing;
3. the length of the pendulum from the point at which it is tied to the center of the pendulum bob.

Define

1. pendulum
2. period of a pendulum
3. amplitude of a pendulum
4. Label the parts of a pendulum:
   • A _____________________________
   • B _____________________________
   • C _____________________________
   • D_____________________________

Materials

• 3 rubber stoppers of the same mass
• stopwatch
• string
• protractor
• pendulum clamp
• meter stick
• ring stand

Procedure

In this lab you will determine the relationship between the period of a pendulum and its mass, amplitude, and length. Discuss the best procedure for accomplishing this purpose with your lab partners. Be sure to repeat your trials to minimize error.

Record and organize your data in the generic data tables on the back of this page. Be sure to title each column and row with the quantity you are measuring.

Part II

1. Attach a softball to the end of your pendulum string, and set the motion detector level with the bottom of the swing of the pendulum.
2. Allow the pendulum to swing back and forth, toward and away from the motion detector.
3. Collect data on the displacement vs. time graph on the computer screen.
4. When you get a good graph for a particular length of the pendulum, save it to your H: drive.

Questions

1. What does the graph remind you of?

2. Sketch the graph on the axes below. Be sure and label each axis with the appropriate values.

3. From the graph, what is the

(a) period of the pendulum? ______________________________

(b) frequency of the pendulum?____________________________

(c) amplitude of the pendulum? ____________________________

(d) maximum speed of the pendulum? _______________________