Date: Fri, 15 Oct 2004 12:19:49 -0400 (EDT)

Author: Richard Berg

Subject: Re: localized energy mode demo, i.e pendulum revisited


For small amplitudes, they might end up all moving back and forth together
in phase.

For large amplitudes, they might end up moving back and forth with
adjacent pendula out of phase.

But then again, they might not.


On Fri, 15 Oct 2004, sampere wrote:

> I saw the coolest demo yesterday. Al Sievers from Cornell gave a
> colloquium here yesterday and brought a demo with him.
> Picture a dozen small identical pendulms suspended from a single rod,
> perhaps from a bearing, so the rod does not play any role in
> transferring energy. Then, connect each of the pivot points with
> springs so that as the pendulums oscillate, the springs either wind up
> or unwind. The direction of oscillation is perpendicular to the length
> of the suspension rod, i.e., if the pendulums all dangle from rod
> horizontal and parallel to your screen, the pendulums oscillate in and
> out of the screen.
> So, here are two questions for you:
> 1) For small starting amplitudes, the initial conditions for all pendula
> being equal, what do expect to see?
> 2) Same as 1, but for very large starting amplitudes?
> I'll post the answer later after I hear your thoughts.
> Sam

Dr. Richard E. Berg, Professor of the Practice
Director, Physics Lecture-Demonstration Facility
U.S. mail address:
Department of Physics
University of Maryland
College Park, MD 20742-4111
Phone: (301) 405-5994
FAX: (301) 314-9525
From Fri Oct 15 09:41:05 2004