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Re: Waves

At 04:28 PM 7/4/00 -0700, Leigh Palmer wrote:
>> The high pitched precursor
>>to the main pulse is likely due to the transmission of longitudinal
>>modes in the cable at speeds higher than those of the transverse mode.
>
>Yes, but why is "modes" in the plural for longitudinal? Would one expect
>the cable to transmit longitudinal waves with a range of speeds? Why?

Please excuse my sloppy terminology; there is only one longitudinal
mode, of course. The transmission of compressional waves in solids is
dispersive,

Aha. I did not know or had forgotten this.


but I don't think I can give a good answer to your "why"
question. The transmission of transverse waves in a stiff string is
also dispersive, by the way.

I find it hard to say "why" dispersion occurs even when the mathematics
seems clear. This is strange because it's usually the other way round for me.

Mark