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Homework Help: Help! Freefalling object problem!

  1. Aug 29, 2008 #1
    1. The problem statement, all variables and given/known data
    A certain freely falling object requires 1.60 s to travel the last 23.5 m before it hits the ground. From what height above the ground did it fall?

    2. Relevant equations
    This is my last question on my online homework. Help! I have gotten answers, but the computer says they wrong.

    3. The attempt at a solution
    I know I have to set up two different equations, one for the last 23.5 m and one from the point that it fell at to the last 23.5m. I know the initial Velocity of the object is 0, and the final velocity of the initial drop is the initial velocity of the last 23.5m. Please help! I have tried it numerous times. My hw is due in 4 hours.... Thanks :)
  2. jcsd
  3. Aug 29, 2008 #2


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    Science Advisor
    Homework Helper

    You know the equations for a faling object.
    v = u + gt
    s = ut + 1/2 gt^2
    v^2 = u^2 + 2gs

    (s=distance, u=initial velocity, v=final velocity)
    So you can work out the initial velocity ofthe last stage, and then use that as the final velocity of the first stage.
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