Dropped soldiers It is told that during World War II the Russians, lacking suffi

Question

Dropped soldiers It is told that during World War II the Russians, lacking sufficient parachutes for airborne operations, occasionally dropped soldiers inside bales of hay onto snow. The human body can survive an average pressure on impact of 30 lb/in2. Suppose that the lead plane drops a dummy bale equal in weight to a loaded one from an altitude of 100 ft, and that the pilot observes that it sinks about 2 ft into the snow. If the weight of an average soldier is 180 lb and his effective area is 5 ft2, is it safe to drop the men?

Explanation / Answer

h =100 ft
m=144 lb
x = 2 ft
A = 5 ft^2

The work done on the falling body is zero from jump to landing so
0 = m*g*h - F* x
F = m*g*h /  x

We know, Pressure = Force /Area
Pressure = m*g*h / A*x
Pressure = (180 *100) / (5 * 2)
Pressure = 1800 lb/ft^2
Converting to inches -
Pressure = 12.5 lb/in^2

So yes we can clearly say, it is safe to drop men.

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