Question 1

A 0.15 kg baseball is pitched at 40 m/s and is hit straight back at 60 m/s. What is the magnitude of the impulse delivered to the ball by the bat?

Accepted Answer

$$15.0\ \mathrm{kg\cdot m/s}$$

Question 2

Which of the following best describes an inelastic collision?

Accepted Answer

Objects collide and stick together, generating heat and possibly deforming.

Question 3

A 2 kg cart moving at 3 m/s collides and sticks to a 1 kg cart at rest. What is their final velocity after the collision?

Accepted Answer

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

Question 4

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

Accepted Answer

$$m_1v_{1,\mathrm{initial}} + m_2v_{2,\mathrm{initial}} = m_1v_{1,\mathrm{final}} + m_2v_{2,\mathrm{final}}$$

Question 5

A 70 kg astronaut in space throws a 2 kg wrench away from herself at 5 m/s. What is her recoil velocity?

Accepted Answer

$$-0.14\ \mathrm{m/s}$$

Question 6

Which of the following statements about elastic collisions is correct?

Accepted Answer

Both momentum and kinetic energy are conserved.

Question 7

A 0.5 kg ball moving at 4 m/s collides elastically with a stationary 0.5 kg ball. What is the velocity of the first ball after the collision?

Accepted Answer

$$0\ \mathrm{m/s}$$

Question 8

A force of 10 N acts on a 2 kg object for 0.5 seconds. What is the change in momentum of the object?

Accepted Answer

$$5\ \mathrm{kg\cdot m/s}$$

Question 9

Which of the following is the correct formula for impulse?

Accepted Answer

$$F \Delta t$$

Question 10

A 3 kg object moving at 2 m/s collides inelastically with a 2 kg object moving at 1 m/s in the same direction. What is their final velocity?

Accepted Answer

$$1.6\ \mathrm{m/s}$$

Question 11

A car of mass 1000 kg traveling at 20 m/s crashes into a wall and comes to rest in 0.1 s. What is the average force exerted by the wall on the car?

Accepted Answer

$$200,000\ \mathrm{N}$$

Question 12

Which of the following best explains why airbags reduce injuries in car accidents?

Accepted Answer

They increase the time over which the momentum changes, reducing the force.

Question 13

A 0.2 kg hockey puck slides on ice at 10 m/s and is stopped by a player in 0.05 s. What is the average force applied by the player?

Accepted Answer

$$40\ \mathrm{N}$$

Question 14

Which of the following is NOT a requirement for the conservation of momentum in a system?

Accepted Answer

The objects must have equal masses.

Question 15

A 5 kg object moving at 6 m/s collides elastically with a 2 kg object at rest. What is the velocity of the 2 kg object after the collision?

Accepted Answer

$$8.57\ \mathrm{m/s}$$

Question 16

Which of the following real-life scenarios best illustrates the concept of impulse?

Accepted Answer

A tennis player hitting a ball with a racket, changing its speed and direction.

Question 17

A 0.1 kg rubber ball is dropped from 2 m and bounces back to 1.5 m. Which type of collision does this best represent?

Accepted Answer

Partially inelastic collision

Question 18

If the net external force on a system is zero, which of the following statements is true?

Accepted Answer

The total momentum of the system remains constant.

Question 19

A 0.3 kg ball moving at 5 m/s collides head-on with a 0.2 kg ball moving at -2 m/s. If the collision is perfectly elastic, what is the velocity of the 0.3 kg ball after the collision?

Accepted Answer

$$2.2\ \mathrm{m/s}$$

Physics Exam Review: Momentum, Work & Energy, Rotational Motion, Gravitation, and Kinematics

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