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Limit word problem- helicopter jump

  1. Oct 16, 2006 #1
    Hi, I need help with this question

    At a publicity event, Ayida, a stuntperson, will jump out of a helicopter with a jetpack on her back. The jetpack allows her to achieve a net upward acceleration of 4.4m/s^2 for a single interval of maximun lenght 10s. Ayida wants to time the use of the jetpack so that she lands with a zero velocity.
    a) If the helicpter is 100m hight, when should Ayida turn on her jetpack? When will she land?
    b) If the helicopter is 200m hight, when should Ayadia turn on her jetpack? when will she land?
    c) What is the maximum height from wich Ayida can jump to land with zero velocity?

    I don't know where to start can someone explain this problem thanks.
  2. jcsd
  3. Oct 16, 2006 #2
    Use the equation [tex] y = y_{0} +v_{y0}t + \frac{1}{2}a_{y}t^{2} [/tex]. You can differentiate this to get [tex] v_{y} = v_{y0}+a_{y}t [/tex]
    Last edited: Oct 16, 2006
  4. Oct 16, 2006 #3
    How did you get that equation?
  5. Oct 16, 2006 #4


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    Homework Helper

    It's a 'standard' equation of displacement for motion with constant acceleration.
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