Please explain with all the steps BECAUSE I DONT UNDERSTAND THIS SHIT In Februar

Question

Please explain with all the steps BECAUSE I DONT UNDERSTAND THIS SHIT

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 56 m/s (terminal speed), that his mass (including gear) was 85 kg, and that the magnitude of the force on him from the snow was at the survivable limit of 1.2 x J(}' N. What are (a) the minimum depth of snow that would have stopped him safely and (b) the magnitude of the impulse on him from the snow?

Explanation / Answer

(a) His KE at the time of collision is 1/2mv2 = 1/2*85*562 = 133280 J

Suppose he stops after going to depth h in ice.

Work done by resistiv force in stopping him = F*h = 1.2*105*h

Energy conservation yields, 1.2*105 *h = 133280

So, h = 1.11 m

(b) Deceleration a = F/m = 1.2*105/85 = 1411.76 m/s2

Using equation v = u - at we have,

0 = 85 - 1411.76*t

So time required to stop t = 0.06 s

So impulse = F*t = 1.2*105*0.06 = 7225 N-s

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