Question 1

Which of the following best describes the difference between elastic and inelastic collisions?

Accepted Answer

In elastic collisions, both momentum and kinetic energy are conserved, while in inelastic collisions, only momentum is conserved.

Question 2

A 2 kg cart moving at $$3\ \mathrm{m/s}$$ collides elastically with a stationary 2 kg cart. What are the final velocities of both carts after the collision?

Accepted Answer

$$v_1 = 0$$\ \mathrm{m/s},\ $$v_2 = 3$$\ \mathrm{m/s}$$

Question 3

Which equation correctly expresses the conservation of momentum for a two-object system before and after a collision?

Accepted Answer

$$m_1 v$$_{1i} + $$m_2 v$$_{2i} = $$m_1 v$$_{1f} + $$m_2 v$$_{2f}$$

Question 4

A low-friction glider of mass $$m$$ and speed $$v$$ collides inelastically with a stationary wall and sticks to it. What is the final speed of the glider?

Accepted Answer

$$0$$

Question 5

A 1 kg glider moving at $$4\ \mathrm{m/s}$$ collides and sticks to a stationary 2 kg glider. What is the final speed of the combined gliders?

Accepted Answer

$$1.33\ \mathrm{m/s}$$

Question 6

Which of the following statements about impulse is correct?

Accepted Answer

Impulse is the change in momentum, given by $$J = F \Delta t.$$

Question 7

A 3 kg glider moving at $$2\ \mathrm{m/s}$$ collides elastically with a stationary 1 kg glider. What are the final velocities of both gliders?

Accepted Answer

$$v_{3kg} = 0.5\ \mathrm{m/s},\ v_{1kg} = 3.5\ \mathrm{m/s}$$

Question 8

Which of the following is true for an isolated system during a collision?

Accepted Answer

Momentum is always conserved, but kinetic energy may not be.

Question 9

A ball of mass $$m$$ moving at velocity $$v$$ hits a stationary ball of mass $$2m$$ and sticks to it. What is the final velocity of the combined mass?

Accepted Answer

$$v/3$$

Question 10

Which of the following best describes the role of the environment in energy bar charts?

Accepted Answer

The environment can do work on the system, changing the system's energy.

Question 11

A 2 kg glider moving at $$5\ \mathrm{m/s}$$ collides elastically with a stationary 3 kg glider. What is the final velocity of the 2 kg glider?

Accepted Answer

$$1\ \mathrm{m/s}$$

Question 12

Which of the following is the correct formula for momentum?

Accepted Answer

$$p = m v$$

Question 13

A 1 kg glider moving at $$6\ \mathrm{m/s}$$ collides and sticks to a stationary 3 kg glider. What is the final speed of the combined gliders?

Accepted Answer

$$1.5\ \mathrm{m/s}$$

Question 14

In a real-world car crash, why is the impulse experienced by the passengers greater if the collision time is shorter?

Accepted Answer

Because the force experienced is greater when the collision time is shorter, given $$J = F \Delta t$$ and $$\Delta t is $$small.

Question 15

A 2 kg glider moving at $$3\ \mathrm{m/s}$$ collides elastically with a stationary 6 kg glider. What is the final velocity of the 2 kg glider?

Accepted Answer

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

Question 16

Which of the following is NOT a step in the problem-solving strategy for conservation of momentum?

Accepted Answer

Guess: Estimate the answer without calculations.

Question 17

A 1 kg glider moving at $$2\ \mathrm{m/s}$$ collides elastically with a stationary 3 kg glider. What is the final velocity of the 3 kg glider?

Accepted Answer

$$1.5\ \mathrm{m/s}$$

Question 18

Which of the following scenarios best illustrates the conservation of momentum in a real-world context?

Accepted Answer

A gun recoils backward when a bullet is fired forward.

Question 19

If the environment does work on a system, how is this represented in an energy bar chart?

Accepted Answer

By an increase in the system's energy bars.

Question 20

A 2 kg glider moving at $$4\ \mathrm{m/s}$$ collides and sticks to a stationary 2 kg glider. What is the final speed of the combined gliders?

Accepted Answer

$$2\ \mathrm{m/s}$$

Impulse and Momentum: Conservation, Collisions, and Problem Solving

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