Deck 93: Braking System Principles

Question 1

All of the following are correct statements about braking EXCEPT ________.

A)Kinetic energy of a vehicle doubles when the speed doubles
B)Kinetic energy must be absorbed by the braking system
C)If the vehicle weight is doubled, the kinetic energy of a moving vehicle is doubled
D)The heavier the vehicle, the greater the kinetic energy when moving

Answer 1

Kinetic energy of a vehicle doubles when the speed doubles

Question 2

Technician A says that the front brakes do most of the braking because the front brakes are larger. Technician B says that due to weight transfer, most of the braking force needs to be done by the front brakes. Which technician is correct?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Answer 2

Technician B only

Question 3

The brake pedal assembly uses a mechanical lever to ________.

A)Increase the distance the brake pedal needs to be depressed by the driver
B)Decrease the driver's force on the brake pedal applied to the master cylinder
C)Allow for clearance between the brake pedal and the floor when the brakes are applied
D)Increase the driver's force on the brake pedal applied to the master cylinder

Answer 3

Increase the driver's force on the brake pedal applied to the master cylinder

Question 4

The friction between two surfaces is affected by all of these EXCEPT ________.

A)Surface finish
B)Frictional material
C)Speed difference between the two surfaces
D)Heat

Question 5

Technician A says that the thicker or heavier the disc brake rotor, the more heat can be absorbed. Technician B says that the faster the vehicle is traveling when the brakes are applied, the greater the amount of heat created in the brake system. Which technician is correct?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 6

All of the following are types of brake fade EXCEPT ________.

A)Mechanical fade
B)Rotor fade
C)Lining fade
D)Gas fade

Question 7

Brake fade caused by water can occur ________.

A)Due to moisture in the air on a humid day
B)Only if the vehicle is driven in water above the centerline of the axle
C)Whenever driving through water puddles or during a severe rainstorm
D)Whenever it rains and the roads are wet or damp

Question 8

What can the driver do to reduce the possibility of brake fade caused by heat?

A)Shift the transmission into neutral and allow the vehicle to coast down long or steep hills
B)Ride the brakes to keep the shoes and pads against the drum or rotor
C)Select a lower transmission gear
D)Pump the brake pedal while descending a steep hill

Question 9

Maximum deceleration rates for a typical passenger car or light truck is ________.

A)200 to 250 ft/sec²
B)16 to 32 ft/sec²
C)1 to 3 ft/sec
D)5 to 10 ft/sec

Question 10

Disc brake pads can reach temperatures as high as ________.

A)2000 degrees F (1093 degrees C)
B)300 degrees F (150 degrees C)
C)1300 degrees F (700 degrees C)
D)1000 degrees F (540 degrees C)

Question 11

Rear brakes do less work during hard braking than the front brakes because ________.

A)The rear brakes are larger
B)The vehicle weight transfers forward
C)The rear tires have less traction
D)Both B and C are correct

Question 12

The front brakes on a vehicle do more work than do the rear brakes. Technician A says that this is because the front wheel cylinders are closer to the master cylinder than are the rear wheel cylinders. Technician B says that this is because the weight of a vehicle shifts to the front during a stop. Which technician is correct?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 13

Energy is a measure of work.

Question 14

Work is the transfer of energy from one physical system to another.

Question 15

Weight has a greater effect on kinetic energy than speed.

Question 16

A body in motion tends to remain in motion in a straight line unless acted upon by an outside force.

Question 17

Leverage is a mechanical principle used to increase force.

Question 18

Mechanical advantage is the ratio of force applied to the energy exerted.

Question 19

The static friction coefficient is always higher than the kinetic friction coefficient.

Question 20

The process of braking is the conversion of kinetic energy into heat energy through friction.

Question 21

If the weight of a car doubles, its kinetic energy ________.

A)Doubles
B)Triples
C)Is cut by one-quarter
D)Is cut by half

Question 22

Weight transfer during braking is caused by ________.

A)Weight bias
B)Inertia
C)Friction
D)Brake bias

Question 23

A typical hanging brake pedal is a ________.

A)Fourth-class lever
B)Third-class lever
C)First-class lever
D)Second-class lever

Question 24

The coefficient of friction is found by ________.

A)Multiplying the weight force by the tensile force
B)Multiplying the tensile force by the weight force
C)Dividing weight force by tensile force
D)Dividing tensile force by weight force

Question 25

What factors determine the friction coefficient?

A)Friction material, surface area
B)Surface area, friction material
C)Friction material, surface finish
D)Surface area, surface thickness

Question 26

A 3000 pound vehicle is calculated to have a kinetic energy of 90,000 ft-lb at 28 mph. If the speed of the vehicle remains the same and the weight is doubled to 6000 pounds, what will happen to the calculated kinetic energy?

A)It will increase by the square (x 4), to 360,000 ft-lb.
B)It will remain the same.
C)It will increase proportionally (x 2), to 180,000 ft-lb.
D)None of these are correct.

Question 27

It takes 50 pounds of force to move a 100 pound block of wood across the floor. The coefficient of friction is ________.

A)0.5
B)1.0
C)1.5
D)2.0