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Homework Help: Gravitational Field question

  1. May 25, 2005 #1
    I am having some difficulty with this question:
    A satellite is in orbit around Earth at an altitude of 3700 km. How much must its speed increase, in km/h, to escape the Earth's force of gravity?

    I'm stumped. Please help
  2. jcsd
  3. May 25, 2005 #2
    Whats Earth's escape velocity?
    What velocity is it orbitting at if its at that altitude?
  4. May 25, 2005 #3
    Earth's escape velocity = 1.12 x 10^4 m/s
    and the velocity at that altitude is what im having tourble with
  5. May 25, 2005 #4
    Find the gravitational potential energy at that altitude. What doy ou know about the satelite's KE if it remains at that point?
  6. May 25, 2005 #5
    i think i get what your saying ..

    Ek = 1/2 |Eg|
    [tex]\frac{1}{2}mv^2 = \frac{1}{2}\frac{GMm}{r} [/tex]

    after i find that .. do i subtract that velocity from the escape velocity of earth?
    Last edited: May 25, 2005
  7. May 25, 2005 #6
    Fix your tex tags, slash them the other way, /tex
  8. May 25, 2005 #7
    You've got all youj need to solve the problem.
  9. May 25, 2005 #8
    alright thanks ... appreciate it
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