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Gravational field

  1. Mar 26, 2007 #1
    Some believe that the positions of the planets at the time of birth influence the newborn. Others deride this and say that the gravitational force exerted on a baby by the obstetrician is greater than that exerted by the planets. To check this claim, first calculate the gravitational force exerted on a 5.7 kg baby by a 87.9 kg doctor who is 1.0 m away.

    ok so i am going to use the formula F=G(m1m2)/r^2 and that would be

    F=6.67x10^-11(87.9*5.7)/.5^2 which yeilds 1.32 x10^-7 N which is not the right answer

    what am i doing wrong
  2. jcsd
  3. Mar 26, 2007 #2


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    You have 0.5 for your distance. It should be the 1 m. It is the total distance between the objects you need here.
  4. Mar 26, 2007 #3
    time to call in a replacement--seriously if the center of gravity between the doc and the mom is a meter, those are long forceps. just a joking aside.
  5. Mar 26, 2007 #4
    the equation calls for the radius squared and so i was using .5^2
  6. Mar 26, 2007 #5
    I think the radius is the distance between the two objects centers. This is different than how we usu think of circles and distance.
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