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Finding Altitude

  1. Aug 30, 2009 #1
    1. (a) Find the altitude above the Earth's surface where Earth's gravitational field strength would be four-fifths of its value at the surface. Assume re = 6.371*10^3 km.

    (b) Find the altitude above the Earth's surface where Earth's gravitational field strength would be one-fifth of its value at the surface.


    2. Relevant equations
    g= GMe/re^2
    G= 6.67*10^-11 Nm^2/kg^2
    Me= 5.98*10^24 kg



    3. I am so lost when I try to solve this problem. Could someone please guide me in the right direction to solving this problem. I would greatly appreciate it.
     
  2. jcsd
  3. Sep 1, 2009 #2

    tiny-tim

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    Hi slu1986! :smile:

    (try using the X2 and X2 tags just above the Reply box :wink:)

    This is a dimensions question …

    (like, if the radius is multiplied by three, how much is the surface area multiplied by?)

    so ask yourself, on what power of r does the gravitational field strength depend? :wink:
     
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