"Randy Poe" wrote in message om...
Anonymous wrote in message rg...
Apostrophes got stripped off of the last post. Post reformatted so that it wont matter.

A particle travels in frame S0 with identical velocities in the x and y
directions and with zero velocity in the z direction.

To understand this paradox, youll first need to find the following
matrices:

(a) A Lorentz transformation, L, from S0 to the particles rest frame,
S1.
(b) A Lorentz transformation in the y direction, Ly, from S0 to S2,
that brings the y component of the velocity to zero.
(c) A Lorentz transformation in the x direction, Lx, from S2 to S3,
that brings the particles velocity to zero.
(d) Find the product of Lx and Ly.

Note that the product of Lx and Ly is not the same as L.

First reaction: What? This is trivially wrong. Easy to prove that
the combination of Lx and Ly is L.

Well, it's easy to prove that the combination is not L,
and that Lx Ly is not the same as Ly Lx.
Compare with 2 consecutive rotations in space.
Think Rubik's cube.

His arrogance has misguided both you and Bjoern ;-)

Dirk Vdm