10.2

Pendulum Motion

Student Notes

A simple pendulum oscillates with a well-defined period (the time for one complete swing cycle). What determines that period? You can control the pendulum length, the mass, and the amplitude of the swing. Try different combinations of these values, and determine which can change the period. Then answer the following questions, which will show quantitatively how the period depends on some of these values. Note that it would be hard to change g, the gravitational constant, in a real experiment, but we can do it easily here in simulation.
Questions:

1. | How can you measure the period of the pendulum?
2. | For the default settings, what is the pendulum period in seconds (approximately)?
3. | What happens to the period if you double the length of the pendulum?
4. | What happens to the period if you double the mass?
5. | What happens to the period if you double the gravitational acceleration?
6. | What happens to the period if you double the amplitude, as long as the amplitude is still small?

Self-test

1. | Which of the following affect the period of a simple pendulum: mass, length, amplitude if kept small?
2. | What could you do to a simple pendulum to reduce its period by a factor of two?

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