Question 1

Which of the following best describes why momentum is considered a vector quantity?

Accepted Answer

Because both force and velocity are vectors, and momentum is derived from them.

Question 2

A 97.5 kg running back moves at 7 m/s northeast. He is tackled by a 115 kg linebacker moving at 5 m/s, 30 degrees south of east. What is the correct method to find the total momentum of the system?

Accepted Answer

Add the momentum vectors using vector addition.

Question 3

Which equation correctly expresses the impulse delivered to an object?

Accepted Answer

$$F \Delta t = \Delta p$$

Question 4

Why do air bags reduce injuries in car accidents?

Accepted Answer

They increase the time over which the collision occurs, reducing the average force.

Question 5

A tennis ball (m = 57.5 g) bounces elastically off a wall at an angle of 60° to the normal. If the collision lasts 10 ms, which formula would you use to calculate the average force exerted by the wall?

Accepted Answer

$$F_{avg} = \frac{\Delta p}{\Delta t}$$

Question 6

In an isolated system with no net external force, which statement about momentum is correct?

Accepted Answer

Momentum is conserved.

Question 7

A bullet is fired from a gun. Which principle explains why the gun recoils backward?

Accepted Answer

Conservation of linear momentum.

Question 8

Why do nuclear power plants use water to slow down neutrons?

Accepted Answer

Hydrogen atoms in water are similar in mass to neutrons, allowing effective momentum transfer via elastic collisions.

Question 9

In a simple inelastic collision, which of the following is true?

Accepted Answer

Momentum is conserved, but mechanical energy may not be.

Question 10

If the initial momentum of a system is zero, what must be true after an isolated interaction?

Accepted Answer

The final momentum is also zero.

Question 11

Which equation represents the change in momentum due to a force over a time interval?

Accepted Answer

$$\Delta p = F \Delta t$$

Question 12

A Martian lander uses air bags to survive impact. What is the main physics reason for this?

Accepted Answer

Air bags increase the time of collision, reducing the average force on the lander.

Question 13

Which of the following is a correct statement about the transfer of energy via momentum in gases and liquids?

Accepted Answer

It is fundamental to heat transfer, diffusion, and particle transport.

Question 14

During an elastic collision, what happens to the kinetic energy and momentum of the system?

Accepted Answer

Both kinetic energy and momentum are conserved.

Question 15

A wrench is thrown in space from a stationary astronaut. What happens to the astronaut?

Accepted Answer

The astronaut moves in the opposite direction to conserve momentum.

Question 16

Which formula correctly expresses the momentum of an object?

Accepted Answer

$$p = m v$$

Question 17

In a collision, if the particles stick together, what type of collision is this?

Accepted Answer

Perfectly inelastic collision.

Question 18

Which of the following is a correct application of the impulse-momentum theorem in real life?

Accepted Answer

A baseball bat delivers a large force over a short time to change the ball's momentum.

Question 19

If a neutron collides elastically with a hydrogen atom in water, what happens to its momentum?

Accepted Answer

It transfers a significant portion of its momentum to the hydrogen atom.

Question 20

In a simple inelastic collision, the lost mechanical energy can be released as:

Accepted Answer

Sound, heat, light, or stored as potential energy.

Momentum and Its Applications in Physics

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