Friction in Engineering Mechanics: Interactive Learning Quizzes

Question 1

Which of the following is NOT a factor influencing the coefficient of friction?

Accepted Answer

Gravity

Answer

Nature of the surfaces in contact

Answer

Temperature

Answer

Contact pressure

Question 2

A block is resting on an inclined plane with an angle of 30 degrees. What is the maximum angle at which the block will remain stationary?

Accepted Answer

Angle of repose

Answer

Angle of friction

Answer

Critical angle

Answer

Angle of elevation

Question 3

In the scenario of a body sliding down an inclined plane, which force is performing positive work?

Accepted Answer

Force of gravity

Answer

Force of friction

Answer

Normal force

Answer

Tension force

Question 4

When a driver applies brakes on a wet road, the car stops due to:

Accepted Answer

Sliding friction between tires and road

Answer

Rolling friction between tires and road

Answer

Air resistance

Answer

Gravitational force

Question 5

Which device utilizes the principle of friction?

Accepted Answer

Brake pads

Answer

Ball bearings

Answer

Rocket engines

Answer

Solar panels

Question 6

The angle of friction is defined as the angle between:

Accepted Answer

The frictional force and the normal force

Answer

The normal force and the weight of the object

Answer

The force applied and the resultant force

Answer

The weight of the object and the horizontal surface

Question 7

The ratio of limiting friction to normal reaction is known as:

Accepted Answer

Coefficient of static friction

Answer

Coefficient of kinetic friction

Answer

Angle of repose

Answer

Angle of friction

Question 8

A car is traveling at a speed v on a level road. The coefficient of friction between the tires and the road is μ. The minimum distance in which the car can be stopped is:

Accepted Answer

v^2/(2gμ)

Answer

v^2/(gμ)

Answer

v/(gμ)

Answer

v/(2gμ)

Question 9

The force required to pull a body of mass m up a rough inclined plane of inclination θ, with coefficient of friction μ, is:

Accepted Answer

mg(sinθ + μcosθ)

Answer

mg(sinθ - μcosθ)

Answer

mg(cosθ + μsinθ)

Answer

mg(cosθ - μsinθ)

Question 10

According to Coulomb's law of sliding friction, the force of friction is directly proportional to:

Accepted Answer

Normal force

Answer

Coefficient of sliding friction

Answer

Contact surface area

Answer

Sliding velocity

Question 11

A block of mass 10 kg rests on a horizontal surface with a coefficient of static friction of 0.2. What is the maximum force that can be applied to the block without it moving?

Accepted Answer

20 N

Answer

10 N

Answer

30 N

Answer

40 N

Question 12

Which of the following mechanisms relies on the principles of friction to operate?

Accepted Answer

Brake pads

Answer

Ball bearings

Answer

Flywheels

Answer

Springs

Question 13

The coefficient of friction between two surfaces is measured using a:

Accepted Answer

Tribometer

Answer

Clinometer

Answer

Micrometer

Answer

Manometer

Question 14

Which of the following is an advantage of friction?

Accepted Answer

Prevents slipping

Answer

Generates heat

Answer

Causes premature wear

Answer

Reduces efficiency

Question 15

In rolling element bearings, friction is reduced by:

Accepted Answer

Rolling contact

Answer

Sliding contact

Answer

Static contact

Answer

Dynamic contact

Question 16

Which of the following is an example of static friction?

Accepted Answer

A book resting on a table

Answer

A person pushing a crate across the floor

Answer

A ball rolling on a surface

Answer

A car skidding on a wet road

Question 17

Kinetic friction occurs when:

Accepted Answer

Two objects are sliding past each other

Answer

An object is rolling on a surface

Answer

Two objects are approaching each other

Answer

An object is at rest on a surface

Question 18

Friction can be:

Accepted Answer

Both beneficial and harmful

Answer

Neither beneficial nor harmful

Answer

Only beneficial

Answer

Only harmful

Question 19

Friction is a force that:

Accepted Answer

Opposes the relative motion or tendency of relative motion between two objects

Answer

Is only present when objects are in contact

Answer

Always acts in the same direction as the applied force

Answer

Is always greater than the force applied

Question 20

Which of the following factors does NOT affect the coefficient of friction?

Accepted Answer

Surface area

Answer

Material properties

Answer

Surface roughness

Answer

Normal force

Question 21

Friction is always:

Accepted Answer

Opposed to the direction of motion

Answer

Parallel to the direction of motion

Answer

Independent of the direction of motion

Answer

Perpendicular to the direction of motion

Question 22

The coefficient of friction is a dimensionless quantity that can be interpreted as:

Accepted Answer

The ratio of the force of friction to the normal force

Answer

The distance over which an object slides before coming to rest

Answer

The angle between the force of friction and the normal force

Question 23

Friction affects the motion of objects primarily by:

Accepted Answer

Resisting the relative motion of surfaces in contact

Answer

Causing surfaces to stick together

Answer

Increasing the relative motion of surfaces in contact