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Homework Help: Gravitational acceleration

  1. Apr 21, 2005 #1
    At what altitude above Earth's surface would the gravitational acceleration be 3.53 m/s^2?

    I used the equation
    a= GM/r^2
    G=6.67 x 10^-11 and M= 5.98 x 10^24
    Solving for r gives 1.06 x 10^7 m which isn't right... can someone tell me what I'm doing wrong?
  2. jcsd
  3. Apr 21, 2005 #2


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    Reread the question. You need the altitude above the Earth's surface, not the distance from the center of gravity of the earth.
  4. Apr 21, 2005 #3
    How would I find that since all I know is the acceleration, mass and radius of the Earth?
  5. Apr 21, 2005 #4
    You know r = 1.06 x 10^7 m, the problem isnt asking for 'r'.

    The problem is asking how far from earth's surface. You know 'r' of earth, how high above the earth is r = 1.06 x 10^7m?
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