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Intertial mass and determining the value of gamma

  1. Feb 13, 2013 #1
    1. The problem statement, all variables and given/known data
    This is not a problem I was assigned, I am just trying to figure out how I could prove it to myself.

    Basically, I am just wondering WHY the gamma value for relativistic momentum takes the form that it does, namely (1-u^2/c^2)^-.5

    I've tried to prove this to myself a few times and I just cannot figure out how to do it. I am not sure if this is above my skill level and that is why I can't do it, as it was not addressed in my book nor was it addressed in my lecture. I tried to follow the same basic argument I used to show myself the value of gamma in the lorentz transformation, I just cannot figure out why the v^2 changes to u^2.

    Even a qualitative answer would be helpful here.

    Thanks a lot.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Feb 13, 2013 #2


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    Staff: Mentor

    What are v and u in your derivation? That should be the same - the relative velocity between the two reference frames.
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