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Re: Relative motion again

From Sylvia Else <sylvia@email.invalid>
Newsgroups sci.physics.relativity
Subject Re: Relative motion again
Date 2018-11-06 13:16 +1100
Message-ID <g4cbr4F5gouU1@mid.individual.net> (permalink)
References <5a7ad418-fc96-4c4c-b352-140904aeed03@googlegroups.com>

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On 6/11/2018 5:49 am, xip1415926@gmail.com wrote:
> Some guy walks out of a bar…
> 
> Well, almost.
> 
> Actually, two guys walk out of two bars, these guys being of about equal weight, mass = 150 lbs, and equal walking speed, 2 mph. They turn right and left on leaving doorways, thereby approaching each other on the sidewalk.
> 
> Walker-A has speed a = 2 and walker-B has speed b = 2, speeds conveniently positive though of opposite directions.
> 
> Relative motion of the walkers is convergence.  Walkers A and B approach one another with speed v = a + b = 2 + 2 = 4.
> 

This is wrong. You are making the unfounded assumption that velocities 
combine by addition, when they do not. The difference is negligible for 
small velocities, but large when the magnitudes of the velocities 
approach the speed of light.

Sylvia.

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Relative motion again xip1415926@gmail.com - 2018-11-05 10:49 -0800
  Re:Relative motion again Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-11-05 20:16 +0100
    Re:Relative motion again Buck Dehner <uktea@yswdoiz.cp> - 2018-11-05 21:07 +0000
      Re:Relative motion again Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-11-05 22:55 +0100
        Re:Relative motion again Buck Dehner <uktea@yswdoiz.cp> - 2018-11-05 22:46 +0000
          Re:Relative motion again Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-11-06 01:22 +0100
            Re:Relative motion again Ntowicz Usarczyk <iswso@wioioksi.io> - 2018-11-06 20:27 +0000
  Re: Relative motion again Sylvia Else <sylvia@email.invalid> - 2018-11-06 13:16 +1100
    Re: Relative motion again benj <benj.fake@gmail.com> - 2018-11-05 21:45 -0500
      Re: Relative motion again Sylvia Else <sylvia@email.invalid> - 2018-11-06 14:57 +1100
    Re: Relative motion again xip1415926@gmail.com - 2018-11-05 19:58 -0800
      Re: Relative motion again xip1415926@gmail.com - 2018-11-05 21:24 -0800
      Re: Relative motion again Sylvia Else <sylvia@email.invalid> - 2018-11-06 18:10 +1100
      Re: Relative motion again Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-11-06 09:21 +0100
        Re: Relative motion again xip1415926@gmail.com - 2018-11-06 06:03 -0800
          Re: Relative motion again Tom Roberts <tjroberts137@sbcglobal.net> - 2018-11-06 08:41 -0600
            Re: Relative motion again Ntowicz Usarczyk <iswso@wioioksi.io> - 2018-11-06 20:32 +0000
              Re: Relative motion again Tom Roberts <tjroberts137@sbcglobal.net> - 2018-11-06 20:39 -0600
                Re: Relative motion again Ntowicz Usarczyk <iswso@wioioksi.io> - 2018-11-07 19:44 +0000
          Re: Relative motion again Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-11-06 22:32 +0100

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