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Homework Help: Finding initial vertical velocity given acceleration

  1. Sep 14, 2015 #1
    1. The problem statement, all variables and given/known data
    Sam heaves a shot with weight 16-lb straight upward, giving it a constant upward acceleration from rest of 45.4 m/s^2 for a height 65.0 cm . He releases it at height 2.16 m above the ground. You may ignore air resistance.

    Q-What is the speed of the shot when he releases it?

    2. Relevant equations:
    Equations I believe I can use are
    V=initial V +at or
    V^2=initial V^2 +2a(x-initial x)

    3. The attempt at a solution
    Since the final velocity would be zero when it is at the highest point i got
    0=initial V^2 +2(45.4m/s^2)(-.65m)
    I would have V ^2=59.02
    then V=7.68m/s
    but this says it is wrong when i check my answer.
    Please help
  2. jcsd
  3. Sep 14, 2015 #2

    Doc Al

    User Avatar

    Staff: Mentor

    The final velocity is the velocity when he releases it--that's not zero. It starts at zero.

    Nonetheless, the equation is correct and so is your answer. Are you sure you are posting the exact problem?
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