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Homework Help: Kinematic question

  1. Sep 12, 2007 #1
    1. The problem statement, all variables and given/known data

    The height of a helicopter above the ground is given by h = 2.60t3 , where h is in meters and t is in seconds. After 2.00 s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground?

    2. Relevant equations

    yf=y(initial) + v*delta t

    3. The attempt at a solution

    h = 2.60 (8) = 20.8 (height at the bag is released)
    v= 7.8t^2= 31.2 m/s
    i dun understand if gravity would be used here and if it is can u just use the quadratic eqn
  2. jcsd
  3. Sep 12, 2007 #2


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    Homework Helper

    Everything you did looks good. Yes, you'll have to use the quadratic equation.
  4. Sep 12, 2007 #3


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    Homework Helper

    this equation isn't right since velocity isn't constant... but you didn't use this equation.
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