Re: Hewitt Special Relativity Example (Long)

[John Mallinckrodt <ajm@CSUPOMONA.EDU>]

I wrote:

> But if there is a simple argument that has eluded me, I'd
> like to hear it.  Hewitt offers none ...

Oops.  While I think this was once the case in earlier editions of
Hewitt and is also, I believe, the case in the video, I note that
Hewitt does now include a lengthy footnote justifying the inverse
relationship with a clever argument that involves considering a
spaceship that is 1) traveling from Earth to another planet that is
motionless wrt earth, 2) receiving periodic signals from Earth, and
3) sending signals of its own in sync with the received frequency
which then travel along with those from Earth to the other planet.

It is interesting, however, to note that his argument might well
*seem* to apply equally well to sound waves; the reason it doesn't is
a little subtle.  To his credit, he does *say* that it doesn't apply
to waves that require a medium, but he doesn't explain why.

--
John Mallinckrodt        mailto:ajm@csupomona.edu
Cal Poly Pomona          http://www.csupomona.edu/~ajm

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.