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Homework Help: Orbital Velocity

  1. Mar 10, 2010 #1
    I have a homework problem that involves the equation v=sqrt((g*R^2)/r) I am confused as to where this equation comes from. I know that Vcirc = sqrt((GM)/r) and Vesc = sqrt((2GM)/r)
     
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  3. Mar 10, 2010 #2

    ideasrule

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    Do you know the formulas a=v^2/r and a=GM/r^2? Equate the two and you get v^2/r=GM/r^2. With a bit of manipulation, you get that equation.
     
  4. Mar 10, 2010 #3
    a=v^2/r is the equation for the normal component of acceleration

    a=GM/r^2 derived from F= GMm/r^2

    a satellite orbiting the earth only has a normal component of acceleration correct ?
     
  5. Mar 10, 2010 #4
    this is the problem. Why can't you just use v^2=GM/r?
     

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  6. Mar 10, 2010 #5

    ideasrule

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    For a circular orbit, yes.
     
  7. Mar 10, 2010 #6

    ideasrule

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    You can. That comes from equating v^2/r with GM/r^2.
     
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