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Gravity Acceleration problem

  1. Apr 21, 2005 #1
    On planet Zog, Mr Spock measures that it takes 1.41 s for a mass of 0.3 kg to hit the ground when released from rest from a height of 3.09m. Calculate the size of acceleration of gravity on that planet.
    I know that a= GM/r^2, but I don't know the radius. Any suggestions on where to begin?
  2. jcsd
  3. Apr 21, 2005 #2
    Assuming that the height from which the mass is dropped is negligable compared to the radius, this is a trick question.
  4. Apr 21, 2005 #3
    I don't believe you need to use the equation you gave. Use a simple kinematic equation.

    [tex]d = v_{i}t + \frac{1}{2}at^2[/tex]

    You know d, vi, and t. Solve for a.

    EDIT: Maybe this won't work, but it seems right to me. The mass shouldn't matter, as everything accelerates at he same rate, regardless of mass.
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