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Homework Help: Crazy problem about impulse

  1. Nov 10, 2007 #1
    1. The problem statement, all variables and given/known data

    In February 1955, a paratrooper fell 370 m from an airplane without being able to open his chute but happened to land in snow, suffering only minor injuries. Assume that his speed at impact was 60 m/s (terminal speed), that his mass (including gear) was 80 kg, and that the force on him from the snow was at the survivable limit of 1.2*10^5 N.

    (a) What is the minimum depth of snow that would have stopped him safely?

    (b) What is the magnitude of the impulse on him from the snow?

    2. Relevant equations

    delta P = F*t

    3. The attempt at a solution

    I have no clue, I've never seen a problem like this before...
  2. jcsd
  3. Nov 10, 2007 #2
  4. Nov 10, 2007 #3


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    Homework Helper

    Paratrooper's mass and treminal velocity is given. Find his KE when he touches the ground. Finally he stops. Change in KE = Force X Displacement.
  5. Nov 10, 2007 #4
  6. Nov 10, 2007 #5
    I found KE, but what does that have to do with impulse? I thought impulse was change in momentum?
  7. Nov 10, 2007 #6
    impulse is mV1-mV2
  8. Nov 10, 2007 #7
    but KE will tell u what velocity the man lands at the snow
  9. Nov 10, 2007 #8
    mv1 - mv2...is that like P1 - P2? (P stands for momentum)
  10. Nov 10, 2007 #9
    Yes. Now that you have kinetic energy, you have everything you need to solve this.
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