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Homework Help: Distance of a satellite from the earths surface.

  1. Oct 24, 2011 #1
    1. A television satellite is in circular orbit about the Earth, with a sidereal period of exactly 24h. What is the distance from the Earths surface?

    2. I think I have to use Kepler's Laws. Confused as to how to do it without the mass of each. I guess I could find out the mass of the earth but then..? Can anyone point me in the right direction?
  2. jcsd
  3. Oct 24, 2011 #2
    GMm/r2 = ω2r

    GM/r = ω2

    You know G and M (or can look them up)

    ω is the angular velocity. If the period is 24 hours then you know 24 hours is the amount of time it takes for the satellite to travel 2∏ radians. You should probably convert that into radians/sec
  4. Oct 24, 2011 #3
    Thanks! :)
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