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Re: SLINKY



What a coincidence, John's message flushed on my screen only
several seconds after my reply. Thanks for additional clarifications.

John Denker wrote:

Be careful, there are three pieces of physics here, and you mentioned
only two; we have not only

a) transverse waves driven by tension, and
b) longitudinal waves driven by compression/extension, but also
c) transverse waves driven by stiffness .........

I just discovered a misconception in my ways of thinking about
transverse waves. Am I the only one who was not aware of the
third kind of waves in a stretched spring? The textbooks I know
totally ignore contribution of stiffens to the speed of transverse
waves. And their "derivation" of the formula v=sqr(T/mu) is
nearly artificial (based on the centripetal force). I would not
accept the derivation without knowing that it happens to lead
to correct answer.

And why do we emphasize formal derivations in physics if the
only acceptable validation is experimental? Physicists do need
mathematics to make discoveries at least as much as our cousins,
mathematicians, need experimental data to stimulate their minds.
Ludwik Kowalski