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Re: Relativistic rotating disc

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Le 08/08/2023 à 22:45, JanPB a écrit :
> On Tuesday, August 8, 2023 at 9:24:47 AM UTC-7, Richard Hachel wrote:
>> Relativistic rotating disc. 
>> 
>> We talk about that very little, and as a specialist in relativistic 
>> kinematics, I understand very well why. 
>> 
>> It's not easy to talk about that. 
>> 
>> Some may even have fits of terror, it's so complicated. 
>> 
>> The solution requires small baby steps. 
>> 
>> Very important the small steps of babies in relativity. 
>> 
>> Fundamental, even. 
>> 
>> R.H.
> 
> It's for the same reason Newtonian mechanics using accelerated observers
> is not as commonly discussed, it requires a decent command of at least
> vector calculus and some linear algebra. The added complication in
> the case of special relativity is that the time variable is related to proper
> time by a function (not the identity function). Other than that there is nothing
> terribly exotic in it, theoretically speaing.
> 
> --
> Jan

The relativistic spinning disc poses an obvious problem, just as 
Langevin's traveler poses an obvious problem.

The obvious problem, in Langevin's traveler, is not the fact that there is 
a paradox in the reciprocal positive chronotropy of the two protagonists 
(that is to say that the INTERNAL mechanism of their watch beats 
constantly faster that the other shows, which may seem absurd in the end), 
is that there is a total blindness of physicists on the clear description 
of the phenomenon, and a total ignorance of the covariance of the apparent 
reciprocal relativistic effects.

But I talked about that, and if it can make the idiots laugh who don't 
understand what I'm saying, let them laugh!

The other problem, that of the spinning disc, is that physicists agree 
that the time at the periphery expands, that the circumference contracts, 
but that they do not understand anything at all of what is happening. for 
the radius, considered invariant.
We then enter a kind of madness, with a space in the shape of a horse 
saddle and other fun things.

However, if we apply the invariance of the speed of light, as we do for 
the Poincaré-Lorentz transformations, we realize that there will also be, 
progressively, as the disk rotates, a similar contraction of the radius, 
so that if the circumference becomes C'=C.sqrt(1-v²/c²) where c is the 
tangential velocity,
the radius undergoes the same thing, and "pi" remains constant.

I talked about this on a post of the day on fr.sci.physics

Those who speak French can go and read.

The calculations are simple and the concept obvious, starting from the 
invariant speed of light.

Doctor Richard Hachel 

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Relativistic rotating disc Richard Hachel <r.hachel@frite.fr> - 2023-08-08 16:24 +0000
  Re: Relativistic rotating disc "mitchr...@gmail.com" <mitchrae3323@gmail.com> - 2023-08-08 10:59 -0700
  Re: Relativistic rotating disc JanPB <filmart@gmail.com> - 2023-08-08 13:45 -0700
    Re: Relativistic rotating disc Richard Hachel <r.hachel@frite.fr> - 2023-08-08 21:02 +0000
      Re: Relativistic rotating disc "mitchr...@gmail.com" <mitchrae3323@gmail.com> - 2023-08-08 17:09 -0700
      Re: Relativistic rotating disc Maciej Wozniak <maluwozniak@gmail.com> - 2023-08-08 21:38 -0700
      Re: Relativistic rotating disc JanPB <filmart@gmail.com> - 2023-08-08 22:28 -0700
        Re: Relativistic rotating disc Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-08-08 22:39 -0700
          Re: Relativistic rotating disc Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-08-09 19:13 -0700
  Re: Relativistic rotating disc Sylvia Else <sylvia@email.invalid> - 2023-08-09 19:12 +1000
    Re: Relativistic rotating disc Richard Hachel <r.hachel@frite.fr> - 2023-08-09 12:27 +0000
      Re: Relativistic rotating disc Sylvia Else <sylvia@email.invalid> - 2023-08-09 22:39 +1000
        Re: Relativistic rotating disc Richard Hachel <r.hachel@frite.fr> - 2023-08-09 12:52 +0000
      Re: Relativistic rotating disc Athel Cornish-Bowden <athel.cb@gmail.com> - 2023-08-09 19:14 +0200
        Re: Relativistic rotating disc Richard Hachel <r.hachel@frite.fr> - 2023-08-09 17:35 +0000

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