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Homework Help: Gravitational field of mars

  1. Dec 19, 2008 #1
    1. The problem statement, all variables and given/known data
    A 250-kg space probe weighs 935 N on the surface of Mars. What is the gravitational field strength on the surface of Mars?

    2. Relevant equations

    3. The attempt at a solution
    Okay, so at first I thought it would be:
    g=3.75 m/s^2


    Then I remembered the weight of the probe...What do I do with that?

    Oh wait, brainflash.

    If I went W=mg and changed it to g=W/m
    =3.74 m/s^2

    ...So which answer is right?
  2. jcsd
  3. Dec 19, 2008 #2


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    In the first case you have calculated the gravitational acceleration of the probe, that is the acceleration at which a unit mass will experience if it placed a distance r from the probe in the absence of any other fields.

    The latter answer is correct.

    Do you now understand why?
  4. Dec 19, 2008 #3
    Yeah, thanks! That helps! :)
  5. Dec 20, 2008 #4


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    Since both answers were the same, where was the problem?

    I would go with the second solution method, since that is simpler and it makes direct use of the given information about mass and weight.
  6. Dec 20, 2008 #5


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    How very true. I hadn't noticed that the OP had used the mass of Mars!
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