[Phys-L] TPT article on momentum & reference frames
From: antti.savinainen at KUOPIO.FI (Savinainen Antti)
Date: Sun Oct 2 16:29:36 2005
Hi all,
I got my copy of the October issue of The Physics Teacher a few
days ago; there was a quite interesting article
"When is momentum conserved and what about car crashes
in Virginia?". However, it seems to me that he made a small (?)
mistake when writing about an orbiting shuttle:
"Astronauts inside the shuttle would find that momentum is
conserved for collisions of objects in *their* accelerated
noninertial reference frame". (the emphasis added by me)
I have thought that the frame *inside* the shuttle would be
a free float frame (as Spacetime Physics by Taylor & Wheeler
put it). Hence it would be a (local) inertial frame instead
of "accelerated noninertial reference frame". Of course,
the shuttle is accelerating as judged from the reference
frame fixed to the Earth.
Regards,
Antti
Antti Savinainen, Ph.D., B.Ed.
Senior Lecturer in Physics and Mathematics
Kuopio Lyseo High School
Finland
E-mail: <antti.savinainen@kuopio.fi>
Website: <http://kotisivu.mtv3.fi/physics/>
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