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Homework Help: Finding loss of sun's mass given the energy density delivered.

  1. Feb 2, 2013 #1
    1. The problem statement, all variables and given/known data

    The energy density (energy per unit area per unit time) arriving from the sun at the surface of the earth is 1300 J/m2s. Calculate the mass loss of the sun in one year. (The earth is about 1.49 x 1011 m from the sun.)

    2. Relevant equations

    ΔE = Δmc2

    KE = (γ-1)mc2

    3. The attempt at a solution

    I'm not sure how to calculate the loss of energy density from the sun as a function of distance. I feel like it can't be as easy as plugging the energy into E=mc2
  2. jcsd
  3. Feb 2, 2013 #2


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    Hint: You're not given an energy; you're given an energy density.
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