Question 1

Which of the following best describes an internal force within a system?

Accepted Answer

A force exerted by one part of the system on another part within the same system.

Question 2

According to Newton's Third Law, which statement is correct?

Accepted Answer

For every force, there is a force of equal magnitude and opposite direction.

Question 3

A person pushes a box across the floor. Which of the following is an example of an external force acting on the box?

Accepted Answer

The friction between the box and the floor.

Question 4

If two forces act on an object in opposite directions and are equal in magnitude, what is the net force on the object?

Accepted Answer

$$F_{net} = 0$$

Question 5

Which of the following scenarios best illustrates Newton's Third Law?

Accepted Answer

A swimmer pushing water backwards and moving forward.

Question 6

A system consists of two blocks connected by a rope. If block A pulls on block B with a force $$F$$, what is the force that block B exerts on block A?

Accepted Answer

$$F$$

Question 7

Which of the following is NOT a key concept from Chapter 5-5.2?

Accepted Answer

Thermal Energy

Question 8

If a book is sitting on a table, which force is the reaction force to the book's weight?

Accepted Answer

The normal force exerted by the table on the book.

Question 9

A rocket launches upward. What is the action-reaction pair according to Newton's Third Law?

Accepted Answer

The rocket pushing exhaust gases downward and the gases pushing the rocket upward.

Question 10

Which equation correctly represents the relationship between action and reaction forces?

Accepted Answer

$$F_{action} = -F_{reaction}$$

Question 11

A person stands on a skateboard and pushes against a wall. What happens according to Newton's Third Law?

Accepted Answer

The wall pushes back on the person, causing the skateboard to move.

Question 12

Which of the following statements about forces is true?

Accepted Answer

Forces can cancel each other out and have a net force of zero.

Question 13

If a car is at rest and the forces acting on it are balanced, what is the net force on the car?

Accepted Answer

$$F_{net} = 0$$

Question 14

Which of the following is an example of a system where internal forces do not change the motion of the system as a whole?

Accepted Answer

Two ice skaters pushing off each other on frictionless ice.

Question 15

A student pulls a wagon with a force of $$10\,N to $$the right, while another student pulls with $$10\,N to $$the left. What is the net force on the wagon?

Accepted Answer

$$0\,N$$

Question 16

Which of the following best describes a reaction force?

Accepted Answer

A force that is equal in magnitude and opposite in direction to the action force.

Question 17

If a swimmer pushes water backwards with a force of $$50\,N$$, what is the magnitude and direction of the force exerted by the water on the swimmer?

Accepted Answer

$$50\,N$$ forwards

Question 18

Which of the following is a correct statement about systems and forces?

Accepted Answer

External forces are required to change the motion of the system as a whole.

Question 19

A ball is dropped from a height. Which force is responsible for its acceleration?

Accepted Answer

External force (gravity)

Question 20

Which of the following is the best definition of a system in physics?

Accepted Answer

A group of objects chosen for analysis, which may interact with both internal and external forces.

Forces: Internal and External Forces in Physics

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