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Homework Help: Forces question HELP!

  1. Sep 18, 2005 #1
    When you lift a bowling ball with a force of 82 N, the ball accelerates upward with an acceleration a. If you lift with a force of 99 N, the ball's acceleration is 8 x a.
    (a) Find the weight of the bowling ball.
    N
    (b) Find the acceleration a.
    m/s2


    Ok, i found part (a), which is 78.48 N. Now, on part (b) why wouldn't the acceleration be 99 N/ 8 kg, which is 12.37 m/s2???? :confused:
     
  2. jcsd
  3. Sep 18, 2005 #2

    Doc Al

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    Staff: Mentor

    What's the net force on the ball?
     
  4. Sep 18, 2005 #3

    HallsofIvy

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    Science Advisor

    Did you forget that you have to lift with the weight of the ball just to get it moving at all? The force in "F= ma" is 99N- mg.

    As usual, Doc Al got there before me!
     
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