Question 1

A hockey puck slides across perfectly smooth ice with no friction. According to Newton's first law, what will happen to the puck?

Accepted Answer

It will continue moving in a straight line at constant speed unless acted upon by a net force.

Question 2

Which of the following best describes a force?

Accepted Answer

A force is a push or pull exerted by an agent on an object.

Question 3

A 2 kg block is pulled across a table by a horizontal force of 10 N. If the frictional force opposing the motion is 4 N, what is the acceleration of the block?

Accepted Answer

$$a = \frac{10 - 4}{2} = 3\ \mathrm{m/s^2$}$$

Question 4

Which of the following is NOT a contact force?

Accepted Answer

Gravitational force

Question 5

A person pushes a box across the floor. The box moves at constant speed. Which statement is true about the forces acting on the box?

Accepted Answer

The applied force is equal to the frictional force.

Question 6

A compressed spring exerts a force on an object. What is the direction of this force?

Accepted Answer

Always away from the spring, pushing the object

Question 7

A 5 kg object is subjected to a net force of 20 N. What is its acceleration?

Accepted Answer

$$a = \frac{20}{5} = 4\ \mathrm{m/s^2$}$$

Question 8

Which of the following statements about Newton's third law is correct?

Accepted Answer

The action and reaction forces are equal in magnitude and opposite in direction.

Question 9

A car crashes into a wall and comes to a sudden stop. The crash dummy inside continues moving forward until it hits the dashboard. This is an example of:

Accepted Answer

Newton's first law

Question 10

If the net force on an object is zero, which of the following must be true?

Accepted Answer

The object moves at constant velocity or remains at rest.

Question 11

A rocket expels hot gases backward. According to Newton's third law, what force acts on the rocket?

Accepted Answer

A force forward, equal in magnitude to the force exerted on the gases.

Question 12

Which of the following is the correct formula for weight near Earth's surface?

Accepted Answer

$$W = m 	imes g$$

Question 13

A 10 kg box is at rest on a horizontal table. What is the magnitude of the normal force exerted by the table on the box?

Accepted Answer

$$n = 98\ \mathrm{N}$$

Question 14

A person stands on a scale in an elevator that is accelerating upward. Compared to when the elevator is at rest, the scale reading will:

Accepted Answer

Be greater than the person's actual weight.

Question 15

Which force is always perpendicular to the surface an object is in contact with?

Accepted Answer

Normal force

Question 16

A 3 kg object is pulled by a rope with a tension of 15 N. If the object moves upward and the only other force is gravity, what is its acceleration?

Accepted Answer

$$a = \frac{15 - 9.8}{3} = 1.73\ \mathrm{m/s^2$}$$

Question 17

Which of the following is an example of a long-range force?

Accepted Answer

Gravitational force

Question 18

If you double the mass of an object while keeping the net force constant, what happens to its acceleration?

Accepted Answer

It halves.

Question 19

A person walking pushes backward on the ground with their foot. What force allows them to move forward?

Accepted Answer

The static friction force from the ground

Question 20

Which of the following best describes the direction of the tension force in a rope?

Accepted Answer

Always in the direction of the rope, away from the object being pulled

Motion and Forces: Newton’s Laws and Fundamental Concepts

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