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Re: SR examination question



I consider myself an above average nitpicker, but I also believe I
know when I *am* nitpicking and, IMO, it is definitely *not*
nitpicking to say that this is a *completely* broken question.

I might be willing to live with the unfortunate subliminal
implication of the question that there is, somehow, a preferred
frame if it had at least read something more like either

"When Peter observes the second hand on his watch to have made
one complete revolution, how many revolutions will Peter say
^^^^^^^^^
Jane observes the second hand of her watch to have made?"

(in which case the clearly implied--if still somewhat
ambiguous--answer is 0.46) or

When Jane says Peter observes the second hand on his watch to
^^^^^^^^^
have made one complete revolution, how many revolutions will
Jane observe the second hand of her watch to have made?

(in which case the clearly implied--if still somewhat
ambiguous--answer is 2.3.)

I still don't really like the question, but without some kind of
modification along the lines I have suggested, there is simply no
way of knowing which of these two different reasonable answers are
being solicited.

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

On Thu, 17 May 2001, Rick Tarara wrote:

How many Ph.D. Physicists does it take to......

While all the nit-piks that have been stated are arguably true, I think it
is quite clear what the question intends. Jane's second hand makes 2.29
revolutions while Peter's makes one. The watches don't need to be
synchronized to observe this and the observation is a 'God's Eye View' as is
often the case when talking about time dilation. The assumption that Jane
is at rest and Peter is moving in a straight line are also common to such
problems. At the intended level of the problem, I see nothing that should
confuse the students. Any who could come up with all of our nit-piks should
also be wise enough to understand the intent of the question.