Question

In February 1955, a paratrooper fell 365 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 10^5 N.What is the minimum depth of snow that would have stopped him safely?What is the magnitude of the impulse on him from the snow?

Answer 1

Answer:

a. $i=4760 kg*m/s$

b. $D_U= 1.11 m$

Explanation:

a)

F= 120,000N

Kinetic energy @ impact = 120,000*depth

$K_E= (1/2)*85kg*(56m/s)^2$

$K_E=133280 J$

$D_U= \frac{133280J}{120000N} = 1.11 m$

b)

The momentum is equal to the impulse on him from the snow so:

$p=m*v$

$p=85kg*56m/s$

$i=4760 kg*m/s$