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Homework Help: Relativistic Momentum problem

  1. Feb 2, 2012 #1
    1. The problem statement, all variables and given/known data

    Mass of particle = 5GeV/C^2
    Momentum of particle = 5GeV/c

    Find total energy of particle and speed of particle.

    2. Relevant equations

    E=λmc^2
    p=λmu
    λ=(√(1-(u/c)^2))^-1

    3. The attempt at a solution

    When I try so solve for speed, I realize λ is a function of u, so get this:

    (u*(√(1-(u/c)^2))^-1) = p/m = c, but can't solve for u from that.

    How would I go about approaching this problem?
     
  2. jcsd
  3. Feb 2, 2012 #2

    vela

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    Try finding another relationship between E, p, and m in your textbook.

    You can solve for u in your approach, but your assertion that p/m=c isn't correct.
     
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