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Homework Help: Free Fall Acceleration Problem

  1. Sep 15, 2010 #1
    1. The problem statement, all variables and given/known data

    As a runaway scientific balloon ascends at 19.6 m/s, one of its instrument packages breaks free of a harness and free-falls. The figure below gives the vertical velocity of the package versus time, from before it breaks free to when it reaches the ground.
    2-p-053.gif

    (a) What maximum height above the break-free point does it rise?
    (b) How high is the break-free point above the ground?


    2. Relevant equations



    3. The attempt at a solution

    i know part A is 19.6 m
    i just can't seem to get the correct answer for part B

    these are the variables that i have and i think i'll need
    V0=0 m/s
    t=6.0 s
    a=-9.8 m/s/s
    y-y0=?

    i used this kinematic equation
    y-y0=vt-1/2at^2
    but the answer still isn't correct
     
  2. jcsd
  3. Sep 15, 2010 #2

    kuruman

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    The package is at the break-free point at time t = 2 s and it is moving up. Can you figure out by looking at the graph at what later time it is at the same point, moving down?
     
  4. Sep 15, 2010 #3
    it's at the same point at t=4 s
     
  5. Sep 15, 2010 #4

    kuruman

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    At t = 4 s the velocity is instantaneously zero. This mean maximum height.
     
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