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RE: Wave Velocity




Well, Jack, you are absolutely right -- I *did* know there were lawyers and
HEP people on the list and I *did* write an additional paragraph with all
the pedantic specifics --- but I erased it because I figured that most would
be bored. (:-)

Let me re-state the question for all:

Consider a long (infinitely long if desired) magnetic, flexible medium which
can support an aperiodic wave (no resonance, no reflection at the ends) --
this could be a light iron chain or iron string-like thing. I like the
image of a slinky, but each can choose. This thing is to be held linear by
magic. The ends thereof are fixed. There is tension in the thing,

Let me imagine a long slinky with its upper loop supported by a very strong
and very taut (non-magnetic) flubonium wire which is coated with
frictionless glime. Thus the slinky can move freely but only in the +/-
x-direction. And thus any spontaneously tweak would cause a longitudinal
perturbation which would travel at velocity, V. (If an iron string is
envisioned, the perturbation would be transverse. That would be just fine.)

There is another flubonium wire (equally taut and strong) which is located
directly above and parallel to the first wire, but not touching the slinky
and upon which a magnet can slide and be driven at constant velocity v.

At t=0 the slinky is quiescent. The magnet moves. What is the resultant
motion of the slinky? How do I find an analytic solution? Consider V=v,
V>v, and V<v if you will.

Jack, I hope al the parameters are there. If not, assume somethng simple or
please poke at me again.

Folks, this is a real problem. I hope you will take it seriously.

Copious thanks to all who do. (:-)



Jim Green
JMGreen@sisna.com