Variable Length Pendulum

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 Code Number :   3A95.70  

Disclaimer:

Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

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Condition :   Excellent  
Principle :   Potential to Kinetic Energy, Simple Harmonic Motion  
Area of Study :  Acoustics  
Equipment :   Variable length pendulum, variable length pendulum with aluminum bar and bearing supports.

Procedure :   The variable length pendulum makes use of a plastic bushing at the pivot point to make the pendulum length variable while the pendulum is swinging. This is often used to demonstrate subtle points.  

The variable length pendulum with bearing supports is a more stable system designed to withstand the forces of the swinging pendulum.  This needs to be set up on one of the little tables that has the rod supports and the proper distance.  Even then if the pendulum is given enough energy the whole table will visibly move when the length of the pendulum is varied.

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   References

T. Wickramasinghe, and R. Ochoa, "Analysis of the Linearity of Half Periods of the Lorentz Pendulum", AJP, Vol. 73, # 5, May 2005, p. 442.

 

Ron Hipschman, "Pendulum Table," Exploratorium Cookbook III, p. 188.1 - 188.18.


Mail Questions and Comments to:  Dale Stille