Bob Crantz wrote:

"Martin Baxter" wrote in message
...

Sounds good to me, I don't belive tension (or compression) has anything
to with the speed of transmission in a solid.

Assume a completely rigid guitar neck. Adjusting the tension of the string
adjusts its resonant frequency. If the length does not change, but the
resonant frequency does, then the velocity in the string must change.

C = tension/linear density

I don't think so, you are thinking of resonance in a transverse plane,
not propagation of a sound wave through the medium. Your example is for
a transverse wave, the TDR mode you propose to employ is in fact a
compresion/rarefaction, not unlike the P wave in siesmology. The problem
is going to be "injecting" this pulse, if you just tap the side of the
rod you will generate transverse waves rather than the longitudinal wave
you are seeking. I do not think that that transverse waves will be
reflected by a crack in the rod or the connectors between rod sections.

See http://prola.aps.org/abstract/PRD/v7/i6/p1590_1 for the general
equation.


Cheers
Marty