System Fundamentals

Question 1

The degree of friction is known as

Answer 1

coefficient of friction (COF)

Question 2

The purpose of any vehicle braking system is

Answer 2

to retard the motion of the vehicle through friction

Question 3

C O F formula is

Answer 3

eg 60 lbs pulling force/100 lbs of weight = 0.60 or COF 60%

Question 4

Excessive brake heat may be generated if a vehicle

Answer 4

is overloaded or is speeding

Question 5

4 factors affecting braking performance

Answer 5

1: material drums, rotors and linings are made of.
2: condition of those materials
3: force applied to those materials
4: temperature of those materials

Question 6

When maximum temp rating is exceeded on braking materials and coefficient of is severely reduced, it’s called

Answer 6

Brake Fade

Question 7

Traction is

Answer 7

COF between the vehicles tires and road surface

Question 8

Power is

Answer 8

the rate at which work is done

Question 9

If weight is doubled, stopping distance is

Answer 9

2 times as much

Question 10

the amount of stopping power is _______ times more than acceleration ( 0-60/60-0)

Answer 10

10 times

Question 11

if speed is doubled, stopping distance is

Answer 11

4 times as much

Question 12

if speed and weight is doubled, stopping distance is

Answer 12

8 times as much

Question 13

stopping time is affected by 3 things

Answer 13

reaction time
lag time
braking time

Question 14

operator reaction time is affected by 4 things

Answer 14

fatigue, alcohol or drugs, physical illness, age

Question 15

lag time of 0.3 seconds is normal and affected by

Answer 15

air restrictions, brake adjustment, foundation brake equipment, system moisture and contamination, and air leaks

Question 16

Braking time is time required to stop once the brakes are applied. what are 5 influences

Answer 16

force applied to brake shoes(by the operator), foundation brake condition, vehicle weight and speed, brake lining temperature, traction between tires and road surface

Question 17

3 air brake advantages are

Answer 17

1: Some air leakage will not affect braking
2: Components are light, compact and inexpensive to produce
3: Do not require bleeding

Question 18

2 disadvantages of Air Brakes are

Answer 18

more susceptible to contamination and lag is unavoidable

Question 19

Area = pi R squared or

Answer 19

Area = D squared x 0.7854

Question 20

torque is measured in

Answer 20

lb-ft or N*m

Question 21

Force is measure in

Answer 21

lb or N

Question 22

Length is measured in

Answer 22

in or m

Question 23

The foundation brake is

Answer 23

the mechanical side of the air brake system

Question 24

What happens to temp. and pressure of gas when volume is compressed to half?

Answer 24

They are both doubled

Question 25

What is purpose of air compressor?

Answer 25

To provide a supply of pressurized air for system operation

Question 26

Purpose of governor?

Answer 26

Limit maximum air system pressure.

Question 27

What Canadian law was enacted in the 1970’s?

Answer 27

CMVSS 121