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Homework Help: Gravitational field line

  1. Mar 25, 2010 #1
    Where on an imaginary gravitational field line between Earth and moon, a mass would have no weight neither due Earth nor due to moon?
  2. jcsd
  3. Mar 25, 2010 #2


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    If you mean when the gravitational force is zero, then you just need to equate

    FEarth and FMoon for a mass m and solve for the distance.
  4. Mar 27, 2010 #3
    Thanks for your reply. This was meant to be a straight forward answer without any calculation.
    Since the gravity of the moon is 1/6 that of Earth , does it follow that the distance where there is no gravity on the object is 1/6 the distance between moon and Earth, starting off from the moon?
    Last edited: Mar 27, 2010
  5. Mar 27, 2010 #4


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    No, that 1/6 figure is only true about the surface gravity of the Earth vs. the surface gravity of the moon. It is not applicable everywhere in space.

    I think you really do need to set up an equation using the equation for gravitational force. At least, I can't imagine solving it any other way.
  6. Mar 28, 2010 #5
    Thanks for you answer. I did as you both suggested. The final answer is 1/10 the total distance starting from the centre of the moon.

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