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Homework Help: Physics (Circular Motion)

  1. Sep 29, 2004 #1

    How do I go about finding the Force of Gravity(N) in a circular motion problem.

    My teacher is asking us to solve for that, so wat do I multiply to get that?

    All I need is the formula to find Force of Gravity (N).

    PS. I need it pretty quick because the Homework is do tomorrow.

  2. jcsd
  3. Sep 29, 2004 #2


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    the force of gravity? are you talking about a vertical circular motion?
  4. Sep 29, 2004 #3
    Here is my problem.....

    It is about the planets and orbiting the sun, this is the planet earth

    Period (years) = 1
    Period (seconds)=31,536,000
    Centripetal Acceleration-5.94x10^-3
    Force of Gravity (N)= ?
    Mass (KG)=?
    Centipetal Force (N)=?

    I actually need to solve for those 3 things, if someone could give me the answer to those then that would be great because I have to do 8 other planets after this one so it would get me off to a good start, Thanks

    if not the answer then a formula or something to find them (I really need to know how to find the Force of Gravity (N))
  5. Sep 29, 2004 #4
    The centripetal force (mv^2/r) is supplied by Gravity F=Gmm/r^2

    Sun mass = 2 x 10^30 kg if I remember correctly...
  6. Sep 29, 2004 #5

    So, what does Gmm represent, I know r is radius but wat does Gmm mean
  7. Sep 29, 2004 #6


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    Constant of Gravity (NOT 9.8 m/s^2) and m1 and m2, are the masses of the two objects.
    Last edited: Sep 29, 2004
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