Question 1

A person pushes against a wall with a force of 100 N, as shown in the first image. According to Newton's Third Law, what is the magnitude and direction of the force that the wall exerts on the person?

Accepted Answer

100 N, in the opposite direction to the push

Question 2

A hammer strikes a nail, as shown in the second image. If the hammer exerts a downward force of $$F on $$the nail, what is the force exerted by the nail on the hammer?

Accepted Answer

$$F$$, upward

Question 3

A car's tires push backward on the road, as shown in the third image. According to Newton's Third Law, what is the reaction force?

Accepted Answer

The road pushes the tires forward

Question 4

A rocket launches by expelling gas backward, as shown in the fourth image. What is the action-reaction force pair in this scenario?

Accepted Answer

Rocket pushes gas backward; gas pushes rocket forward

Question 5

When a cannon is fired (see the fifth image), the cannonball and the cannon experience equal and opposite forces. Why does the cannonball accelerate more than the cannon?

Accepted Answer

The cannonball has less mass than the cannon

Question 6

Consider the orange on a cart being pulled by an apple (see the sixth and seventh images). If the apple exerts a force $$F on $$the orange, what is the force exerted by the orange on the apple?

Accepted Answer

$$F$$, in the opposite direction

Question 7

If the apple and orange are considered as a single system (see the eighth image), and there are no external forces, what happens to the acceleration of the system?

Accepted Answer

The system does not accelerate

Question 8

A helicopter hovers in midair. If the lift force equals the helicopter's weight, what is the motion of the helicopter?

Accepted Answer

It hovers in midair

Question 9

A bird flies by pushing air downward with its wings. According to Newton's Third Law, what is the reaction force?

Accepted Answer

The air pushes the bird upward

Question 10

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

Accepted Answer

Both move at the same speed in opposite directions

Question 11

When you step off a curb, Earth pulls you downward. What is the reaction force according to Newton's Third Law?

Accepted Answer

You pull Earth upward

Question 12

Why do you not notice the Earth moving upward when you jump off a curb, even though you pull Earth upward with the same force it pulls you downward?

Accepted Answer

Earth's mass is so large that its acceleration is imperceptible

Question 13

A block of ice rests on a ramp. As the ramp is raised, which force acting on the block remains constant?

Accepted Answer

$$mg ($$the weight of the block)

Question 14

A sled is pulled at an angle, as shown in the image with the dog and girl. Which component of the pulling force is responsible for moving the sled forward?

Accepted Answer

The horizontal component, $$F_x$$

Question 15

A slightly tilted airplane wing deflects oncoming air downward. What is the resulting force on the wing called?

Accepted Answer

Lift

Question 16

If the apple-orange system is moving at constant speed, what must be true about the forces acting on it?

Accepted Answer

A force equal and opposite to the friction force occurs

Question 17

Which of Newton's laws explains why a rocket accelerates upward when it expels gas downward?

Accepted Answer

Newton's Third Law

Question 18

A block of mass $$m is $$acted on by a net force $$F. $$According to Newton's Second Law, what is its acceleration?

Accepted Answer

$$a = \frac{F}{m}$$

Question 19

Which of the following statements about action-reaction force pairs is correct?

Accepted Answer

They always act on different objects

Question 20

A person throws a stone at an angle, as shown in the image with the velocity components. Which statement is true about the vertical and horizontal components of the stone's velocity?

Accepted Answer

They are perpendicular to each other

Newton's Third Law of Motion and Vector Analysis

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