🚀 go-pugleaf

< If the elevator is accelerating, then after a long, long time its speed will
< reach the speed of light then pass it.  I know that the problem here
< has to do with the fact that F=mA is false when the speed approches 'c'.
< In fact F approches infinity near 'c'.  So with a constant (or even increasing
< but finite) force, wouldn't the acceleration necessarly slow down as the rider
< approched 'c' and hence notice that he was in an elevator? 
< In other words, with a constant acceleration eventually you would be going
< at a speed of 'c' with no more acceleration therefore losing the 'gravity'
< feeling.  Then is it impossible to simulate gravity via acceleration for
< a 'long' period of time?
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No.  Constant accelleration means constant in the instantaneous frame of
reference of the elevator passenger.  Such acceleration can be maintained
indefinitely.  To a non-acclelerating observer, the acceleration appears
to decrease in magnitude as the elevator velocity asymptotically approaches
'c'.  This phenomenon is a simple consequence of Lorentz contraction
and time dilation.  The elevator passenger feels constant acceleration,
but never reaches a velocity 'c' with respect to an observer in any
inertial frame.
-- 
Bill Tanenbaum - AT&T Bell Labs - Naperville IL  ihnp4!ihlpg!tan