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Relative velocity

  1. Aug 21, 2011 #1
    i constantly feel that newton was right in measuring the relative velocity.einstein makes use of light which has a limitation of 300000 km/s .It seems as if because light cannot travel more than 300000 km/s we we see the other object moving at lesser speed.
    to confirm that in relative velocity equation we divide(u+v)by only such a factor dependent on product of 2 velocities i.e u*v / product of light velocity i.e c^2.

    so everything is measured with respect to "c" which itselves has a limitation. can anyone help me out with this.
  2. jcsd
  3. Aug 21, 2011 #2


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    Bodhi, can I make a suggestion for you? This is the second thread you have started without a clear question. Instead of starting new threads, why don't you just read existing threads that deal with the subjects you are concerned with? That's what I did for a year before I ever made my first post and I think that is what most people do before they even log on. You can learn a lot that way and it's much quicker because you won't have to wait for any responses.
  4. Aug 22, 2011 #3
    You start with a wrong suggestion, perhaps that's the cause of your problem? Einstein handled relative velocity exactly as Newton did, and light itself isn't important.

    However, Newton assumed that a measurement system isn't affected by a change in velocity, while according to Einstein it is affected by it - for example, it needs a resynchronization of clocks. As a consequence, SR and classical mechanics use different transformations between reference systems that are in relative motion.
    Those are system transformation equations: SR uses the Lorentz transformation instead of the Galilean transformation.
    Do you really know and understand the Galilean transformation? If so, please explain the difference between the relative speed of two things as measured with a reference system, and a system transformation.

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