Coupled Pendulums

[Joe Taylor <jtaylor@HAL.BSCS.ORG>]

Hello Phys-L gang,
> > > I was wondering if anyone would mind sharing their explanation of
the
> > > motion of a coupled pendulum (two or more pendulums suspended from
a
> > > horizontal section of string.
> > >
> > > I set the first pendulum to oscillate and left the second at rest.
Here
> > > is what I seem to be observing when both pendulums are the same
> > > length...
> > >
> > > 1) The first pendulum begins to oscillate (of course)
> > > 2) Shortly after the first, the second pendulum begins to
oscillate as
> > > well .
> > > 3) The two oscillate together for a time and then the first comes
nearly
> > > to rest. When the first comes to rest, the amplitude of the second
seems
> > > to be near its maximum.
> > > 4) The first will begin oscillating again while the second comes
to
> > > rest. Again, the first seems to reach a maximum amplitude when the

> > > second returns to rest.
> > >
> > > When the pendulums are different lengths...
> > >
> > > 1) The first pendulum continues to oscillate at all times
> > > 2) The second pendulum will begin to oscillate then stop,
oscillate then
> > > stop, oscillate then stop, etc.
> > > 3) I am observing this regardless of whether the first pendulum is
the
> > > longer or shorter of the two.
> > >
> > > In both cases,  I  used pendulum bobs of the same mass.
> > >
> > > What is going on here? Is it energy transfer? resonance?
> > >
> > > Thanks in advance for your help.
> > >
> > > Joe Taylor
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