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# Forces that saved a paratrooper's life

A paratrooper pilot fell 360 m after jumping without his parachute opening. He landed in a snowbank, creating a crater 1.5 m deep, but survived with only minor injuries. Assume the pilot's mass was 80 kg and his terminal velocity was 50 m/s.

(a) Estimate the work done by the snow in bringing him to the rest. (in J)
(b) Estimate the average force exerted on him by the snow to stop him. (in N)
(c) Estimate the work done on him by the air resistance as he fell. (in J)

#### Solution Preview

Hello and thank you for posting your question to Brainmass.

(a)

The paratrooper had initial kinetic energy E and initial potential energy U
The snow did work W to stop the paratrooper
At the end, the paratrooper had no kinetic or potential energy.

Therefore:

(E + U) + W = 0

W=-(E+U)

Just before teh paratrooper hit the snow, his kinetic energy was:

E = 1/2 * M * v^2 = 1/2 * 80kg * (50 m/s)^2 = 100000 J

If we set the bottom of the crater as ...

#### Solution Summary

Fully explained calculations estimate the work and forces given by snow and air to save a paratrooper whose parashoot failed to open

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