Question

minimizing force in a collision
when an object falls, it accelerates due to gravity. this causes a force associated with the movement of the object. according to newtons second - law of motion, this force is proportional to the acceleration and the mass of the falling object. however, when a falling object hits the ground, all of this force is concentrated in a very short period of time over which it stops falling. as a result, the force per unit of time is very large. to reduce the force, and thus cause less damage to the object that very quickly stops moving after a fall, many things can be done.
a person jumps to safety from the second - floor of a burning building into a safety net that is held by firefighters. what factor should be considered when trying to minimize force on the person during a collision with the net?

Explanation:

According to Newton's second - law $F = ma$, and the impulse - momentum theorem $J=\Delta p = F\Delta t$. To minimize the force $F$ during the collision of the person with the net, we need to increase the time $\Delta t$ of the collision. This is because for a given change in momentum $\Delta p$ (which is determined by the person's mass and the change in velocity), if $\Delta t$ is larger, the average force $F$ will be smaller.

Answer:

The time of the collision with the net should be increased to minimize the force on the person.