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Planets X & Y

  1. Jul 17, 2008 #1
    1. The problem statement, all variables and given/known data

    Planets X & Y travel in circular orbits around the same star. The ratio of the radii of their orbits is 5:2. 5 years after the planets were aligned, planet x has rotated 92.6 degrees. how many degrees has y traveled in the same amount of time?

    2. Relevant equations


    Wx=phix/t; Wy=phiy/t

    phix= angular of X after t time
    phiy= angular of X after t time

    3. The attempt at a solution

    I just keep getting the wrong answer. I try transferring the ratio of radii to the angular velocities, but i must be doing it wrong.
  2. jcsd
  3. Jul 17, 2008 #2


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    Staff: Mentor

    Check Kepler's third law.
  4. Jul 17, 2008 #3
    thank you so much, that made to ratio a lot less difficult to apply!!
  5. Jul 17, 2008 #4


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    Staff: Mentor

    Note, that third law can be derived from the F=GMm/r^2.
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