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Homework Help: Momentum of proton

  1. Oct 15, 2011 #1
    1. The problem statement, all variables and given/known data

    A proton of rest mass 1.67 x 10^-27 kg is moving at a constant speed of 0.7c

    What is it's momentum?


    2. Relevant equations



    3. The attempt at a solution

    Using E = γmc^2 I obtained;

    E = 2.10 x 10^-10 J


    Then with;

    E^2 = (pc)^2 + (mc^2)^2 and solving for p I got;

    p = 8.47 x 10^-15
     
  2. jcsd
  3. Oct 15, 2011 #2

    Redbelly98

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    I agree.

    That's the correct method, but I'm getting something quite different. It is probably just an arithmetic mistake. Can you show more details of this calculation?
     
  4. Oct 15, 2011 #3
    Are you getting 4.88 x 10^-19 ?
     
  5. Oct 15, 2011 #4

    Redbelly98

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    Yes, with units of kg*m/s.
     
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