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Homework Help: Force Diagram

  1. Mar 10, 2010 #1
    1. The problem statement, all variables and given/known data
    I have to draw a force diagram for a rock dropped off a cliff at the moment of release.
    Is there any force acting upward on the rock at the moment of release?

    2. Relevant equations

    3. The attempt at a solution
    I know the force of gravity acts downward on the rock. My thinking is that the only force acting on the rock at the moment of release is gravity downward, then as it falls there is air resistance upward and a greater force of gravity downward. When a rock hits it's terminal velocity however the forces of gravity and air resistance are equal. Is this correct?
  2. jcsd
  3. Mar 10, 2010 #2


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    Hi cheerspens! :smile:
    Equal and opposite! :biggrin:

    Otherwise, completely correct! :smile:

    (i assume you're supposed to ignore the atmospheric pressure all round the rock :wink:)
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