Question

A person weighs 500 N. If he falls a vertical distance of 15 meters into a pile of hay, what is the average force exerted by the hay if the person stops in 0.12 seconds?

Answer 1

take g=10, we get m=50
use the use kinematic for falling body to calculate the velocity
\[ v = \sqrt{2gh} \]
and
\[ v = a t \]
so we get
\[ F = ma = \frac{m}{t}\sqrt{2gh} \]