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: Relativity



Really? Can we show this? Because it isn't obvious to me. If I
imagine a small cube sitting on a rotating disk with no translational
velocity and allow the disk to rotate at relativistic speed, the cube
will be Lorentz contracted except when it is moving perpendicular to
my line of sight. Now add to that translational motion and I don't
immediately see why the rotational effect should go away.

The actual Lorentz-contracted shape of the disk depends only on the
translational velocity of the disk and not on its angular velocity. The shape
is the same as if the disk was not rotating. Thus the disk would become an
ellipse with an eccentricity of v/c where the original rest-radius is the
semimajor axis along the direction transverse to the motion, and the semiminor
axis is (1 - (v/c)^2)^(1/2) times the rest-radius oriented along the motion.


David Bowman
dbowman@gtc.georgetown.ky.us


Paul J. Camp "The Beauty of the Universe
Assistant Professor of Physics consists not only of unity
Coastal Carolina University in variety but also of
Conway, SC 29528 variety in unity.
pjcamp@coastal.edu --Umberto Eco
pjcamp@postoffice.worldnet.att.net The Name of the Rose
(803)349-2227
fax: (803)349-2926