Q: A 2 kg ball is moving at 3 m/s. What is its momentum?

$$6\ \text{kg}\cdot\text{m/s}$$

Q: A car with mass $$1000\ \text{kg} is at $$rest. What is its momentum?

$$0\ \text{kg}\cdot\text{m/s}$$

Q: A $$3\ \text{kg}$$ object moving at $$2\ \text{m/s}$$ bounces off a wall and returns at $$-2\ \text{m/s}. $$What is the total impulse delivered to the object?

$$12\ \text{kg}\cdot\text{m/s}$$

Q: A $$5\ \text{kg}$$ object moving at $$2\ \text{m/s}$$ collides with a $$3\ \text{kg}$$ object at rest. If the collision is elastic, what is the total momentum before the collision?

$$10\ \text{kg}\cdot\text{m/s}$$

Question 1

A 2 kg ball is moving at 3 m/s. What is its momentum?

Accepted Answer

$$6\ 	ext{kg}\cdot	ext{m/s}$$

Question 2

A car with mass $$1000\ 	ext{kg} is at $$rest. What is its momentum?

Accepted Answer

$$0\ 	ext{kg}\cdot	ext{m/s}$$

Question 3

Which of the following best describes impulse?

Accepted Answer

Impulse is the product of force and time.

Question 4

A $$0.5\ 	ext{kg}$$ ball is thrown with a velocity of $$4\ 	ext{m/s}$$ and caught, coming to rest in $$0.2\ 	ext{s}. $$What is the average force exerted to stop the ball?

Accepted Answer

$$10\ 	ext{N}$$

Question 5

Why do airbags reduce injuries in car accidents?

Accepted Answer

They increase the time of impact, reducing the force.

Question 6

A $$3\ 	ext{kg}$$ object moving at $$2\ 	ext{m/s}$$ bounces off a wall and returns at $$-2\ 	ext{m/s}. $$What is the total impulse delivered to the object?

Accepted Answer

$$12\ 	ext{kg}\cdot	ext{m/s}$$

Question 7

Two identical freight cars, each of mass $$m$$, collide. One is moving at $$v$$, the other is stationary. After a totally inelastic collision, what is their final velocity?

Accepted Answer

$$\frac{v}{2}$$

Question 8

Which scenario best illustrates the law of conservation of momentum?

Accepted Answer

A cannon firing a cannonball, causing the cannon to recoil.

Question 9

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

Accepted Answer

Objects rebound without lasting deformation or energy loss.

Question 10

A $$2\ 	ext{kg}$$ object moving east at $$3\ 	ext{m/s}$$ collides with a $$1\ 	ext{kg}$$ object moving north at $$4\ 	ext{m/s}. $$What is the magnitude of the total momentum after the collision, assuming they stick together?

Accepted Answer

$$\sqrt{(2\$$times3)^2$$ + (1\$$times4)^2$$} = \sqrt{36 + 16} = \sqrt{52} \approx 7.2\ 	ext{kg}\cdot	ext{m/s}$$

Question 11

Which of the following statements about momentum is correct?

Accepted Answer

Momentum is zero for an object at rest.

Question 12

A baseball player catches a $$0.15\ 	ext{kg}$$ ball moving at $$20\ 	ext{m/s} by $$moving his hand backward during the catch, increasing the stopping time to $$0.5\ 	ext{s}. $$What is the average force exerted on the ball?

Accepted Answer

$$6\ 	ext{N}$$

Question 13

Which collision type is characterized by objects sticking together after impact?

Accepted Answer

Totally inelastic collision

Question 14

A $$5\ 	ext{kg}$$ object moving at $$2\ 	ext{m/s}$$ collides with a $$3\ 	ext{kg}$$ object at rest. If the collision is elastic, what is the total momentum before the collision?

Accepted Answer

$$10\ 	ext{kg}\cdot	ext{m/s}$$

Question 15

A soccer ball bounces off a wall. Compared to stopping the ball, why is the impulse greater when it bounces?

Accepted Answer

Because the ball's momentum changes direction, resulting in a larger change in momentum.

Question 16

If the time of impact in a collision is doubled, what happens to the average force for the same change in momentum?

Accepted Answer

The average force is halved.

Question 17

A $$1\ 	ext{kg}$$ object moving at $$5\ 	ext{m/s}$$ collides with a $$2\ 	ext{kg}$$ object moving at $$-3\ 	ext{m/s}. $$What is the total momentum before the collision?

Accepted Answer

$$-1\ 	ext{kg}\cdot	ext{m/s}$$

Question 18

Which of the following is NOT a real-world example of increasing collision time to reduce force?

Accepted Answer

Slamming your hand against a wall.

Question 19

A $$0.2\ 	ext{kg}$$ ball moving at $$10\ 	ext{m/s} is $$caught and thrown back at $$-10\ 	ext{m/s} in$$ $$0.1\ 	ext{s}. $$What is the average force exerted?

Accepted Answer

$$40\ 	ext{N}$$

Chapter 6: Momentum – Physics with Calculus Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards