🚀 go-pugleaf

In article <1992Dec11.202853.8041@murdoch.acc.Virginia.EDU>
crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:

> My guess is that torsional perturbations do you in. The levitated [three
> disk magnets connected by long arms] simply flops out of your carefully
> arranged [three ring magnets] and proceeds to ... resting on the ground.

Dale is correct.  I was focusing on the arms on the *assumption* that the
disk-over-ring arrangement was capable of creating a shallow but real
potential well that provided lateral stability.  After trying it out with
some real magnets, I'm now convinced that this potential well does not
really exist, and thus the entire arrangement cannot depend on its lateral
stability.

Experimentally, the non-existent potential well of which I'm speaking is
an interesting sort of tactile illusion -- you can run a disk over a ring
with your hands and rather easily persuade yourself that there is a well
of some sort there (there is) *and*, more importantly, that it retains
the ability to repel the disk magnet while simultaneously providing a
certain degree of lateral stability.  And in fact, both of those attributes
*are* true -- you can get some repulsion with some lateral stability.

What's not obvious until you start making more careful versions of the
experiment, however, is that the potential well is like a failing elevator
-- it's inherently unstable, and once the disk magnet falls a little ways
into it the repulsion effect begins to drop rapidly.  Entering this little
well thus means a trip on down to the bottom

And guess what?  The lateral stabilization effect does not exist *until*
you drop into the well, at least just a wee little bit -- which is all
it takes to destabilize and drop down to the bottom.

(And anywho, it gave me a great excuse to play around with magnets again,
which I *always* enjoy doing!)

				Cheers,
				Terry