How Does Snow Impact Paratrooper Survival Physics?

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SUMMARY

The discussion centers on the physics of a paratrooper's survival after falling 380 meters and landing in a snowbank. Key calculations involve estimating the work done by the snow, the average force exerted by the snow, and the work done by air resistance. The paratrooper, weighing 76 kg and reaching a terminal velocity of 50 m/s, survived with minor injuries due to the snow's cushioning effect. The calculations for kinetic energy (KE) and gravitational potential energy (GPE) are crucial for determining the work done and forces involved.

PREREQUISITES
  • Understanding of kinetic energy (KE) and gravitational potential energy (GPE)
  • Basic knowledge of Newton's laws of motion
  • Familiarity with the concept of terminal velocity
  • Ability to perform unit conversions and dimensional analysis
NEXT STEPS
  • Calculate the work done by the snow using the formula W = KE + GPE
  • Determine the average force exerted by the snow using F_av = ma
  • Analyze the work done by air resistance during free fall
  • Explore the effects of different landing surfaces on impact forces
USEFUL FOR

This discussion is beneficial for physics students, aerospace engineers, and safety analysts interested in the dynamics of free fall and impact forces in parachuting scenarios.

gschwarz
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Ive been trying to figure this out and i keep getting stuck.

A paratrooper pilot fell 380 m after jumping without his parachute opening. He landed in a snowbank, creating a crater 1.4 m deep, but survived with only minor injuries. Assume the pilot's mass was 76 kg and his terminal velocity was 50 m/s.

(a) Estimate the work done by the snow in bringing him to the rest.

(b) Estimate the average force exerted on him by the snow to stop him.

(c) Estimate the work done on him by the air resistance as he fell.


For part a i tried setting KE+GPE=W

so .5*76*50^2+76*9.8*380=W

I got 378024 J and it was incorrect. I don't know if some of my units are wrong or if my steps for solving part a are wrong.

Any help regarding parts b and c would be appreciated too.






The Attempt at a Solution

 
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In vacuum, you know what his KE at the point of hitting the ground should be. But it's less. Where's the deficit?

His KE + PE just before hitting the ground is known. In absence of snow, it should be same at any point. Again, how much is the deficit?

F_av = ma. If initial and final speeds are known, then a can be found, and thus F_av.
 

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