Physics 10 | Momentum Quiz

When jumping from some height, why is it safer to bend your knees while landing?

Because by doing so, you extend the time it takes for your momentum to decrease and thus reducing the resulting force on your bones.

In terms of momentum why are nylon ropes, which stretch under a tension load, favored by mountain climbers over less stretchy ropes?

Because there emend the time during which momentum decreases, thereby decreasing the jolting force of the rope.

While driving in your car (but coasting in neutral at constant velocity with no friction), if an insect hits the windshield of the car, how does its momentum change compare with the car's?

By Newton's Third Law, the insect and the car will each undergo equal and opposite changes in momentum.

In terms of momentum, why do padded dashboards make automobiles safer?

Padded dashboards in cars are safer because the passenger hitting the dash has increased time of contact which decreases contact force.

When an object falls from rest and strikes the ground without bouncing, what happens to its momentum?

The momentum of the fallen object is conserved because when the object falls, the Earth and the object move toward each other with equal and oppositely directed momenta and so its final momentum is the same as its initial momentum: zero.

A fully dressed person is at rest in the middle of an ice pond that exerts no friction force. What can be done to get to the shore?

The person can throw an item because the momentum of the thrown object with be accompanied by the thrower's oppositely directed momentum.