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Homework Help: Source of centripetal force

  1. Nov 10, 2004 #1
    Earth goes around the sun. The centripetal force always acts towards the sun. What is the source of this force? Is it gravity?
  2. jcsd
  3. Nov 10, 2004 #2

    James R

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    Gravity is the centripetal force.
  4. Nov 10, 2004 #3
    Gravity isn't a force is it? Gravity isn't defined in Newtons.
  5. Nov 10, 2004 #4
    it is

    F(grav) = (G*m1*m2)/(r^2)

    if you're using vectors you tack on a unit vector to give it direction from the center of mass from one object to the other (and vice versa)
  6. Nov 10, 2004 #5
    you're right, I was thinking about g (acceleration due to gravity), not gravity itself.
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