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Homework Help: Soldier jumps out of a plane

  1. Nov 13, 2015 #1
    1. The problem statement, all variables and given/known data

    A soldier with a machine gun, falling from an airplane gets detached from his parachute. He is able to resist the downward acceleration if he shoots 40 bullets a second at the speed of 500 m/s. If the weight of a bullet is 49 gm, what is the weight of the man with the gun ? Ignore resistance due to air and assume the acceleration due to gravity g = 9.8 m/s2
    2. Relevant equations
    acceleration in place of velocity?

    3. The attempt at a solution
    m_s* v = m_b*v

    But how do i get this velocity
  2. jcsd
  3. Nov 13, 2015 #2
    You could try to recall the relationship between force and momentum, that would explain how the soldier stays in the air.
  4. Nov 13, 2015 #3


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    He fires one bullet; what is the effect on his velocity? If he does that 40 times a second, what acceleration would that produce?
  5. Nov 13, 2015 #4
    I think i have it

    Attached Files:

  6. Nov 13, 2015 #5


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    Yellow text on a white background is going to burn someone's eyes out. :rolleyes:
  7. Nov 14, 2015 #6
    How did you get 49 in your solution since 49 gm / bullet = .049 kg / bullet?
  8. Nov 15, 2015 #7
    I multiplied it by 1/1000
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