Question 1

Which statement best describes Newton’s Third Law of Motion?

Accepted Answer

Whenever one object exerts a force on a second object, the second object exerts a force of equal magnitude and opposite direction on the first.

Question 2

A person pushes against a wall with a force of 200 N. According to Newton’s Third Law, what is the force exerted by the wall on the person?

Accepted Answer

200 N, in the opposite direction.

Question 3

A rocket launches by expelling gas downward. Which statement correctly identifies the action and reaction forces?

Accepted Answer

Action: Rocket pushes gas downward; Reaction: Gas pushes rocket upward.

Question 4

A soccer player kicks a ball with a force of 1500 N. What is the reaction force?

Accepted Answer

The ball exerts a force of 1500 N on the player’s foot, in the opposite direction.

Question 5

When you step off a curb, Earth pulls you downward. What is the reaction force?

Accepted Answer

You pull Earth upward with an equal force.

Question 6

Why do you not notice Earth moving upward when you step off a curb, even though you exert an equal force on Earth?

Accepted Answer

Earth’s mass is so large that its acceleration is extremely small and unnoticeable.

Question 7

A cannon fires a cannonball. If the force exerted on the cannonball is $$F$$, and its mass is $$m_{ball}$$, what is its acceleration?

Accepted Answer

$$a_{ball} = \frac{F}{m_{ball}}$$

Question 8

A bug collides head-on with a fast-moving bus. Which statement is true about the forces during the collision?

Accepted Answer

The force on the bug is equal in magnitude and opposite in direction to the force on the bus.

Question 9

Two people of equal mass push off from each other on slippery ice. What happens to their speeds?

Accepted Answer

Both move at the same speed in opposite directions.

Question 10

An astronaut stranded in space throws a tool away from her ship. What happens next?

Accepted Answer

She moves toward the ship due to the reaction force.

Question 11

When lift equals the weight of a helicopter, what is the helicopter’s motion?

Accepted Answer

It hovers in midair.

Question 12

A bird flies by pushing air downward. What is the reaction force?

Accepted Answer

The air pushes the bird upward.

Question 13

Slightly tilted wings of airplanes deflect oncoming air downward. What is the result?

Accepted Answer

The air exerts an upward force on the wing, producing lift.

Question 14

Compared with a lightweight glider, a heavier glider must push air downward with:

Accepted Answer

Greater force.

Question 15

Which equation represents Newton’s Second Law of Motion?

Accepted Answer

$$F = m 	imes a$$

Question 16

If a car’s tires push backward on the road, what is the reaction force?

Accepted Answer

The road pushes the tires forward.

Question 17

Which of the following is NOT a characteristic of action and reaction forces?

Accepted Answer

They always act on the same object.

Question 18

A man pulls on a spring. What is the reaction force?

Accepted Answer

The spring pulls on the man.

Question 19

If the mass of an object increases while the force remains constant, what happens to its acceleration according to Newton’s Second Law?

Accepted Answer

Acceleration decreases.

Question 20

Which scenario best illustrates Newton’s Third Law in everyday life?

Accepted Answer

A swimmer pushes water backward and moves forward.

Newton’s Third Law of Motion: Forces and Interactions

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