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Homework Help: Gravitational Force of Three Identical Masses

  1. Sep 2, 2008 #1
    1. The problem statement, all variables and given/known data

    Three identical masses of 550 each are placed on the x axis. One mass is at X1= -10.0 , one is at the origin, and one is at X2= 43.0 .
    What is the magnitude of the net gravitational force on the mass at the origin due to the other two masses?

    G = 6.673 x 10-11

    2. Relevant equations

    I'm using just the regular force of grav.

    F_grav= GMm/R^2

    Net force:
    F_net= F1-F2

    and I tried Gm^2(1/X1^2-1/X2^2)

    I'm getting logical numbers, but they're not right.

    I calculated Force1 to be -0.00202
    I calculated Force2 to be 0.00109

    I think I may have squared the mass to get the these numbers...what do I do with the masses? there are three of them, do I use 1650? or 550?
  2. jcsd
  3. Sep 2, 2008 #2
    got it
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