Re: rigid motion not possible in accelerating frame of reference

"Dono" <sa_ge@xxxxxxxxxxx> wrote in message
news:1186291421.611207.142480@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Aug 4, 8:55 pm, "rot...@xxxxxxxxx" <rot...@xxxxxxxxx> wrote:

I do know the Bell's paradox quite well. And no, it does not *require*
knowledge of accelerated motion in SR. (although the full effects do
require it). The conclusion that the rope breaks is found by the
simple logic argument I gave previously:

*If* both ships accelerate (wrt ground) simultaneously and
identically, *then* their separation remain constant (wrt grnd).
Therefore, the rigid rope between them must have the same length
(separation), but this contradicts SR since SR predicts that the rope
(its length) should be Lorentz contracted. Since the rope can not
elongate (its rigid) it must break. IOW, the distance between the
ships remains L but the length of the rope becomes L' < L . Basic
logic.


A simplistic but not very good reasoning. It is predicated on the
(incorrect) BELIEF that "*If* both ships accelerate (wrt ground)
simultaneously and identically, *then* their separation remain
constant (wrt grnd)".

Oh dear little dodo .. in your hurry to score point against others, you've
goofed again.

Turns out that if you use the correct approach (the equations of
hyperbolic motion), the distance between ships is NOT constant, but
increases.

If you are talking about the proper length between them, yes. But as was
very clearly made (even in the section you quoted above) we are taling about
the seperation in the iFoR of the ground. In that frame, they must, by
definition, have the same separation at all times as the acceleration of
both ships is constant and the same. If, in the ground iFoR, the separation
increased, that would mean one shpi acclerated more than the other.

Therefore the rope gets stretched. The conclusion is the
same but the formalism is different.

Yes .. the conclusion was right .. but your criticism was wrong.


.

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