3A40.25 - Ball on a Track vs. Pendulum

Code Number:
Demo Title:
Ball on a Track vs. Pendulum
Simple Harmonic Motion
Area of Study:
Curved Track (with the same arc as the 1 meter pendulum), 1 meter Long Pendulum, 1 Inch Ball Bearings.

Align the track and the pendulum so the ball and the pendulum have the same equilibrium position.  Start them oscillating from the same position.  Note that the pendulum and ball travel the same arc, have the same mathematical form,  but that the ball on the track has a lower frequency.  

  • Laurence A. Marschall, "Driven 'Portulum': A Rolling Ball as a Simple Oscillating System", AJP, Vol. 49, #6, June 1981, p. 557.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.