A - Air Brake System Fundamentals

Question 1

Friction:

Answer 1

Refers to the resistance between two moving bodies.

Question 2

In order to stop a moving vehicle, the braking system must convert moving vehicle energy into:

Answer 2

Heat energy.

Question 3

A vehicle requires 200 hp (149 kW) to accelerate from 0 to 100 km/hr in 60 seconds. If the same vehicle is brought to a complete stop in 60 seconds, the braking system must develop:

Answer 3

2000 hp (1.49 MW).

Question 4

If the weight of a vehicle is doubled, the power required to stop the vehicle will:

Answer 4

Be doubled.

Question 5

If the speed of a moving vehicle is doubled, the power required to stop the vehicle will:

Answer 5

Be increased four times.

Question 6

If both speed and weight of a moving vehicle are doubled, the power required to stop the vehicle will:

Answer 6

Be increased 8 times.

Question 7

One advantage that air brake systems have is that:

Answer 7

The system does not have to be bled when connecting or disconnecting trailers like hydraulic braking systems do.

Question 8

One disadvantage air brake systems is that:

Answer 8

There is always some brake lag.

Question 9

When a given volume of air is compressed to 1/2 its original volume, its pressure will:

Answer 9

Double.

Question 10

When a given volume of air is compressed to 1/2 its original volume, theoretically its temperature will:

Answer 10

Double.

Question 11

A driver makes 40 psi (275.88 kPa) air brake application. If the vehicle is equipped with brake chambers that are 30 in squared (0.019 m squared) in area, each brake chamber will generate:

Answer 11

1200 lb (5.34 kN) of force.

Question 12

The term lag time refers to the time required:

Answer 12

For the air system to apply the brakes.

Question 13

The component of the basic air brake system that connects the air system to the foundation brakes is the:

Answer 13

Brake chamber.

Question 14

The component of the basic air brake system that allows the operator to regulate brake application pressure is the:

Answer 14

Brake valve.

Question 15

The function of the governor is to:

Answer 15

Limit maximum air system pressure.

Question 16

The slack adjusters:

Answer 16

Convert linear motion to rotary motion, multiply the braking force from the brake chamber, and provide a place for brake adjustment.

Question 17

Connecting lines and fittings is important to air brake system operation because they affect:

Answer 17

The speed of air flow through the system.