$$p = 12.05 \times 8 = 96.4\ \mathrm{kg\cdot m/s}$$

$$p = 35 \times 220 = 7700\ \mathrm{kg\cdot m/s}$$\ east

$$p = 700 \times 4.6 = 3220\ \mathrm{kg\cdot m/s}$$\ down\ hill

$$p = 0.5 \times 3.5 = 1.75\ \mathrm{kg\cdot m/s}$$\ along\ road

Question 1

Which of the following best describes the law of conservation of momentum?

Accepted Answer

The total momentum of a system remains constant if no external force acts on it.

Question 2

A 12.05 kg stone rolls down a hill at 8 m/s. What is its momentum?

Accepted Answer

$$p = 12.05 	imes 8 = 96.4\ \mathrm{kg\cdot m/s}$$

Question 3

Which equation correctly represents the conservation of momentum for two objects colliding and moving separately after collision?

Accepted Answer

$$m_1$$ $$u_1$$ + $$m_2$$ $$u_2$$ = $$m_1$$ $$v_1$$ + $$m_2$$ $$v_2$$

Question 4

A 35 kg cannonball is shot east at 220 m/s. What is its momentum?

Accepted Answer

$$p = 35 	imes 220 = 7700\ \mathrm{kg\cdot m/s}$$\ east

Question 5

In an inelastic collision, which of the following is true?

Accepted Answer

The colliding objects stick together and move with a common velocity after collision.

Question 6

A 700 kg log rolls down a hill at 4.6 m/s. What is its momentum?

Accepted Answer

$$p = 700 	imes 4.6 = 3220\ \mathrm{kg\cdot m/s}$$\ down\ hill

Question 7

Which of the following scenarios best represents an explosion in terms of momentum?

Accepted Answer

Two objects initially at rest push off each other and move in opposite directions.

Question 8

A 500 g object rolls along the road at 3.5 m/s. What is its momentum?

Accepted Answer

$$p = 0.5 	imes 3.5 = 1.75\ \mathrm{kg\cdot m/s}$$\ along\ road

Question 9

Three cars travel at 110 m/s. Car 1: 2500 kg, Car 2: 2650 kg, Car 3: 2009 kg. Which car has the highest momentum?

Accepted Answer

Second car

Question 10

Which equation describes the momentum conservation for an inelastic collision where two objects stick together?

Accepted Answer

$$m_1$$ $$u_1$$ + $$m_2$$ $$u_2$$ = ($$m_1$$ + $$m_2) v$

Question 11

Which of the following is a correct statement about elastic collisions?

Accepted Answer

Both momentum and kinetic energy are conserved.

Question 12

Two ice skaters, a woman (54 kg) and a man (88 kg), push off from rest. The woman moves at 2.5 m/s. What is the man's velocity?

Accepted Answer

$$v = -1.5\ \mathrm{m/s}$$

Question 13

Which of the following is NOT a requirement for the law of conservation of momentum to hold?

Accepted Answer

The collision must be elastic.

Question 14

Which of the following best describes the momentum of a system before and after an explosion if the system was initially at rest?

Accepted Answer

The total momentum after the explosion is zero.

Question 15

A 2 kg truck moves east at 3.5 m/s, and a 4.3 kg truck moves south at 1.5 m/s. Which has greater momentum?

Accepted Answer

Second truck at $$7.45\ \mathrm{kg\cdot m/s}$$ due south

Question 16

In a real-world car accident, why is the conservation of momentum a useful principle for investigators?

Accepted Answer

It allows calculation of pre-collision velocities if the masses and post-collision velocities are known.

Conservation of Momentum: Principles, Types of Collisions, and Applications

Study Guide - Practice Questions