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Homework Help: Celestial Mechanics

  1. May 21, 2008 #1


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    1. The problem statement, all variables and given/known data
    a) Calculate the mas of a proton ( ms = 1.67 * 10^-27 kg) whose kenetic energy is half its toral energy. (ANS. 3.34 * 10^ -27 kg)
    b) How fast is it travelling? ( ANS. 0.87c) c- speed of light

    2. Relevant equations

    E(kenetic) = Gm(1)m(2) all over R^2

    E(total) = -0.5Gm(1)m(2) all over R

    V(orbit) = sqrt. GM/r, where M is the mass of planetary object

    E = mc^2

    3. The attempt at a solution

    The most I can come up with is that there is no gravitational potential energy because
    1/2E(k) = E(total)
  2. jcsd
  3. May 21, 2008 #2


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    Staff Emeritus
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    I believe the question is asking for the proton's relativistic mass.
  4. May 21, 2008 #3
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