3A15.10 Physical Pendulum

Concepts

Simple harmonic motion

Overview

A physical pendulum undergoes simple harmonic motion when displaced by a small angle. The oscillations are no longer simple harmonic motion when it is released from a large angle. The pendulum's pivot point can be set at different positions, and two masses can be attached to change the moment of inertia.

Details

Equipment

  • [1] Physical pendulum table
  • [1] Physical pendulum stand
  • [1] Pivot screw
  • [1] Wingnut
  • [2] C-clamp
  • [1] Metal physical pendulum with holes
  • (Optional) [1] Stopwatch
  • (Optional) [2] Screw
  • (Optional) [2] Circular mass
  • (Optional) [2] Wingnut

Classroom Assembly

  1. Place the pendulum stand on the edge of the table.
  2. Clamp the stand to the table using C-clamps.
  3. Attach the pivot screw to the pendulum stand.
  4. Mount the pendulum at any of the holes.
  5. Secure the mounting using a wingnut.

Script

  1. Raise the metal pendulum to a small angle (about 20° or less) and release it.
  2. Now raise the metal pendulum to a large angle and release it.
Optional:
  1. Attach a mass or two using screws and wingnuts and repeat the experiment.
  2. Change the pendulum pivot position and repeat the experiment.
  3. Show using a stopwatch that when the assumption of small oscillations is violated, the pendulum does not undergo simple harmonic motion. The period should vary with oscillation amplitude.

 

Additional Resources

References

  • PIRA 3A15.10

Disclaimer

  • Don't attempt this at home!

Last revised

  • 2018

Technicals

Related AV

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.