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Homework Help: Radius and circles.

  1. Nov 6, 2008 #1
    1. The problem statement, all variables and given/known data
    Communications satellites are placed in orbits such that they rotate the Earth once every 24.0 hours. Determine how high above the Earths surface these satellites must be placed.

    2. Relevant equations
    GM/4(3.14 squared) times T squared

    3. The attempt at a solution
    so i know that first i have to get the radius by using GM/4(3.14 squared) times T squared, and then subract the earths radius from that, but what would be the M in that equation?
  2. jcsd
  3. Nov 7, 2008 #2


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    Science Advisor
    Homework Helper

    Hi livblue23! :smile:

    (have a pi: π :wink:)

    I'm not sure what equation you're using,

    but anyway M would be the mass of the Earth. :smile:
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