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Homework Help: Gravitational force

  1. Mar 21, 2004 #1
    hello everybody:

    A satellite of mass m used in a cellular telephone network is in a circular orbit at a height of h above the surface of the earth.

    What is the gravitational force on the satellite? Take the gravitational constant to be G , the mass of the Earth to be m_e , and the radius of the Earth to be r_e.
    for this question i get the following:
    F_g= (G*m*m_e)/(r_e+h)^2

    now, for this question
    What fraction is this of its weight at the surface of the earth? Take the free fall acceleration to be g.
    i'm going to use just the mass of the earth not the one from the satellite right? but what does it mean "what fraction"?? what formula do i use?
  2. jcsd
  3. Mar 21, 2004 #2
    They want you to find the ratio of the force of gravity acting on the satellite in orbit to the force of gravity acting on the satellite on the surface of the Earth, i.e.

    [tex]\frac{F_g(r_e + h)}{F_g(r_e)}[/tex]

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