Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: A Question of Simultaneity



Note that Robert Cohen's scenario is just a time reversed version of the
scenario which I earlier proposed.

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
www.velocity.net/~trebor
----- Original Message -----
From: "John Mallinckrodt" <ajmallinckro@CSUPOMONA.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, January 25, 2002 6:42 PM
Subject: Re: A Question of Simultaneity


1. If the flashes end up simultaneously at O in the train reference
frame,
do they end up simultaneously at O in all reference frames?

Yes. We can name the event "The two light flashes arrive at O"
without ambiguity. It specifies *a* time and *a* place. Other
observers may use different coordinates to specify *that* time and
*that* place, but they must necessarily agree that there is a
single event that is unambiguously named "The two light flashes
arrive at O".

2. If the speed of the flash pulse along the train is c in the train
reference frame, is the speed also c in a reference frame moving at
speed v
relative to the train?

Yes. The speed of light is the same in all reference frames.

3. If the distance from O to the left-most point is the same as the
distance
from O to the right-most point, is the ratio of the distances also 1 in
a
reference frame moving at speed v relative to the train?

Yes. Both contract by the same factor so the ratio remains one.

Can all three be true?

Evidently!

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