The Torsional Pendulum Demo

P115/P116 Laboratory Demonstration #24

You can click on the image to download it in gif format.

Further information on the Theory, Apparatus, and Procedure, is available. Equipment is stored in Rockerfeller Rooms 402 and 403.

This can be used to demonstrate both conservation of kinetic energy and uniform acceleration of gravity.


Theory

It is known that the period of any type of simple harmonic oscillator is given by the equation:

where the value k is the rotational equivalent of a spring constant. Twisting the disk will induce a restoring torque given by

where theta is the maximum angle of rotation.


Apparatus

The equipment needed for this demo is:

Procedure

Attatch the photogate such that the bolts which protrude from the disk of the pendulum will trigger the photogate. The torsional pendulum is placed on its stand and made to oscillate. The photogate records the time each bolt passes through it. The period should equal approximately two seconds when no weight is added.

To return to the
Mechanics Demo Catalogue .


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