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Homework Help: Universal Gravitation

  1. Nov 23, 2005 #1
    Can anyone help me with this problem?

    Approximate the gravitational force of attraction between a 46.0 kg girl and a 52.0 kg boy if they are sitting 3.0 m apart in physics class.

    Since the formula is [(m1m2/r^2)]G=Fg. So I first tried [(46+52)/3^2]6.67e-11 and I got 7.27e-10. Then when the answer didn't work I thought maybe I was given the diamter, so i divided by 2, so I [(46+52)/1.5^2]6.67e-11, and I got 2.91e-8 and that was wrong to. I only have one more submission left to get this problem right, if you could help me it would be grately appreciated. Is there somthing special I need to do that I am missing? Thank-you
  2. jcsd
  3. Nov 23, 2005 #2


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    Gold Member

    m1m2 = m1 * m2, not m1 + m2
  4. Nov 23, 2005 #3
    yeah thats what i did wrong... thank-you
    Last edited: Nov 23, 2005
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