Question

A 75Kg man jumps from a window 1.0m above the sidewalk. If the man falls with his knees and ankles locked, the only cushion for his fall is an approximately 0.49 cm give in the pads of his feet.
Calculate the average force exerted on him by the ground during this 0.49 cm of travel. This average force is sufficient to cause damage to cartilage in the joints or to break bones.

Answer 1

Answer:

150153.06122 N

Explanation:

m = Mass of person = 75 kg

h = Height of fall = 1 m

g = Acceleration due to gravity = 9.81 m/s²

F = Force

s = Displacement = 0.49 cm

Potential energy is given by

$P=mgh\\\Rightarrow P=75\times 9.81\times 1\\\Rightarrow P=735.75\ J$

Work is given by

$W=Fs\\\Rightarrow F=\frac{W}{s}\\\Rightarrow F=\frac{735.75}{0.0049}\\\Rightarrow F=150153.06122\ N$

The average force exerted is 150153.06122 N