Momentum Review

What is impulse?

• Change in velocity

• Change in momentum

• Rate of change of velocity

• Rate of change of momentum

What is the SI unit of momentum?

• N

• kg · m

• kg · m/s

• kg · m/s^2

What is the equation for linear momentum?

• p=mv

• p=m/v

What is an isolated system?

• A. A system in which the net internal force is zero

• B. A system in which the net external force is zero

• C. A system in which the net internal force is a nonzero constant

• D. A system in which the net external force is a nonzero constant

In the equation p_1 + p_2 = p'_1 + p'_2 for the collision of two objects, what is the assumption made regarding the friction acting on the objects?

• A. Friction is zero.

• B. Friction is nearly zero.

• C. Friction acts constantly.

• D. Friction before and after the impact remains the same.

What is an inelastic collision?

• when objects stick together after impact, and their internal energy is not conserved

• when objects stick together after impact, and their internal energy is conserved

• when objects stick together after impact, and always come to rest instantaneously after collision

• when objects stick together after impact, and their internal energy increases

Consider two objects of the same mass. If a force of 100 N acts on the first for a duration of 1 s and on the other for a duration of 2 s, which of the following statements is true?

• A. The first object will acquire more momentum.

• B. The second object will acquire more momentum.

• C. Both objects will acquire the same momentum.

• D. Neither object will experience a change in momentum.

Cars these days have parts that can crumple or collapse in the event of an accident. How does this help protect the passengers?

• A. It reduces injury to the passengers by increasing the time of impact.

• B. It reduces injury to the passengers by decreasing the time of impact.

• C. It reduces injury to the passengers by increasing the change in momentum.

• D. It reduces injury to the passengers by decreasing the change in momentum.

How much force would be needed to cause a 17 kg · m/s change in the momentum of an object, if the force acted for 5 seconds?

• 3.4 N

• 12 N

• 22 N

• 85 N

A billiards ball rolling on the table has momentum p_1. It hits another stationary ball, which then starts rolling. Considering friction to be negligible, what will happen to the momentum of the first ball?

• It will decrease.

• It will increase.

• It will become zero.

• It will remain the same.