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Homework Help: Acceleration of gravity on an unknown planet.

  1. May 31, 2009 #1
    1. The problem statement, all variables and given/known data
    A 92 kg man weighs 189 Newtons on the surface of an unknown planet. What ist he acceleration of gravity on this planet?

    Basically, I thought the formula to finding the gravitational force was
    G(gm)/r^2, but I'm missing the distance that the man from the planets center is. I don't know where the 189 newtons fit in.

    2. Relevant equations
    G = (gm)/r^2

    3. The attempt at a solution
    G = (gm)/r^2
    G = (6.67x10^-11nm^2/kg^2)(92kg)/r? What is R? I'm totally lost.

    Thank you, appreciate it!
  2. jcsd
  3. May 31, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    It's simpler than all that. If you knew the value of "g" on the planet, how would you find the weight?
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