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Homework Help: Determine the balls mass from force by gravity

  1. Oct 21, 2013 #1
    1. The problem statement, all variables and given/known data
    Two identical balls, their centers 24.0cm apart, experience a mutual gravitational force of 5.3×10−6N .Find the ball's mass

    2. Relevant equations

    Isn't this just backwards?


    6765.28kg? that wasn't right
    i thought it may be in g to i made it to 6.67. still not right
    Does the radius need to be in cm or m?
    3. The attempt at a solution
    i tried it out by using the gravitational force equation
    Last edited: Oct 21, 2013
  2. jcsd
  3. Oct 21, 2013 #2


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    Staff: Mentor

    You chose the correct Relevant equation, for which the constant must be G, not g.

    Make sure that your quantities have units that agree. What are the units of G? How about r?
  4. Oct 21, 2013 #3
    Sorry, but yes it should be G. I did mean G though

    the units are Newtons and Centimeters
    Last edited: Oct 21, 2013
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