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Gravitational Force

  1. Mar 5, 2007 #1
    1. The problem statement, all variables and given/known data
    A bowling ball (mass = 7.2 kg, radius = 0.13 m) and a billiard ball (mass = 0.40 kg, radius = 0.028 m) may each be treated as uniform spheres. What is the magnitude of the maximum gravitational force that each can exert on the other?

    2. Relevant equations
    F = G(m1m2/r^2)

    3. The attempt at a solution
    Im confused about the radius portion of the problem. Shouldn't you add up the radius of both (0.028 + 0.13) and use that answer in the equation?
    Last edited: Mar 5, 2007
  2. jcsd
  3. Mar 5, 2007 #2
    I would think thats as close as the two could come together and therefore the greatest force would be generated. You seem to imply that this is not the case?
  4. Mar 5, 2007 #3
    F = G x m1 x m2 / r^2

    F = (6.67 x 10^-11) x (7.2) x (0.40) / (0.148) x 2

    F = .000000001

    Doesn't seem to be right when I go and check it.
    Last edited: Mar 5, 2007
  5. Mar 5, 2007 #4
    you have .44 above when the problem states .4, and .148 instead of .158 as you suggested using in the denom. maybe follow suit and go to bed as I intend to now.
    Last edited: Mar 5, 2007
  6. Mar 5, 2007 #5
    sorry, I went back and changed everything. Now everything seems to be the way I attempted it.
  7. Mar 5, 2007 #6
    well the denominator still shows 0.148, when its 0.158; also make sure to use exponential entry with your calculator; if it doesn't support such, then use the windows free calculator--use the more advanced of the two available. I get something like 7.7e-9
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