Lesson 13: Friction

Question 1

What is the definition of force?
A) A measure of mass
B) A push or a pull
C) A type of friction
D) A measure of energy

Answer 1

B) A push or a pull

Question 2

What do action-reaction forces do?
A) They cancel each other out.
B) They act on the same object.
C) They do not cancel because they act on different bodies.
D) They are always equal in magnitude.

Answer 2

C) They do not cancel because they act on different bodies.

Question 3

Which of the following is an example of a contact force?
A) Gravitational force
B) Magnetic force
C) Frictional force
D) Electrical force

Answer 3

C) Frictional force

Question 4

What type of friction exists when an object is not moving along a surface?
A) Kinetic friction
B) Dynamic friction
C) Static friction
D) Rolling friction

Answer 4

C) Static friction

Question 5

What is the relationship between the coefficients of static and kinetic friction?
A) μs < μk
B) μs = μk
C) μs > μk
D) μs + μk = 1

Answer 5

C) μs > μk

Question 6

What does the normal force represent?
A) The force of gravity acting on an object
B) The force that opposes motion
C) The perpendicular force exerted on an object by a surface
D) The force applied to move an object

Answer 6

C) The perpendicular force exerted on an object by a surface

Question 7

f an increasing force parallel to the surface is applied on an object and the object does not move, what is happening?
A) The static friction force is greater than the applied force.
B) The kinetic friction force is acting on the object.
C) The applied force is greater than the normal force.
D) The object has reached maximum kinetic friction.

Answer 7

A) The static friction force is greater than the applied force.

Question 8

When an object begins to slide along a surface, what happens to the frictional force?
A) It remains constant.
B) It increases rapidly.
C) It decreases rapidly to the kinetic friction force.
D) It becomes equal to the applied force.

Answer 8

C) It decreases rapidly to the kinetic friction force.

Question 9

Which of the following describes non-contact forces?
A) Forces that act only when objects touch
B) Forces that act at a distance without physical contact
C) Forces that require a medium to act
D) Forces that are always larger than contact forces

Answer 9

B) Forces that act at a distance without physical contact.

Question 10

The coefficient of friction
(𝜇) is typically:
A) Less than 0
B) Greater than 1
C) Between 0 and 1
D) Equal to the mass of the object

Answer 10

C) Between 0 and 1