Mechanical Engineering Quiz # 7

In relation to bending stress, what is the correct value of bending or flexural modulus (Eb), if P is the normal force, L is the beam length, w is the beam width, t is the beam thickness, and y is the deflection at load point?

Eb = PwL/4t2y

Eb = PL3/4wt3y

.Eb = 3PL2/4wt3y

Eb = PL3/4w2ty

Which of the following options can be exchanged in a closed system?

Energy

Matter

Both energy and matter can be exchanged.

Neither energy nor matter can be exchanged.

Express the change in internal energy of the system when no work is done on the system but a certain amount of heat, say q, is taken out from the system and given to the surroundings.

∆U = q + w

∆U = q

∆U = - q

∆U = q - w

Consider the two timber posts that measure 150 millimeters square and 4 meters high. These posts are subjected to an axial load of 108 kN each. How much will they be shorten because of the load, if one post is made of pine timber (E = 7800 MPa)and the other of Australian blackwood (E = 15300 MPa)?

Pine = 8.7 mm, Blackwood = 4.6 mm

Pine = 2.5 mm, Blackwood = 1.3 mm

Pine = 4.5 mm, Blackwood = 0.9 mm

Pine = 1.8 mm, Blackwood = 1.7 mm

Which of the following options are the correct characteristics of the oil-tempered wire?

It is cold drawn and quenched.

It is tempered and general purpose spring steel.

It is suitable for sudden loads.

This question is based upon the figure shown below

What is the significance of the above given symbol in work study technique?

Inspection of materials

Transport of materials

Storage of materials

Operation of materials

In radial tyres

Inner tubes are always used

All plies run parallel to one another and vertical to tyre bead

One ply layer runs diagonally one way and another layer runs diagonally the other way

None of these

The air gap between the central electrode and ground (or side) electrode of a spark plug is around

0.5 mm

1 mm

1.5 mm

0.2 mm

In a unit type body (frameless body) design, the sheet metal parts are welded together, forming a frame work to which outer skin is attached.

True

False

The portion of a crankshaft which rests on cylinder block is called main journal.

Yes

No

In automobiles G.V.W. refers to

Gross vehicle wheel track

Gross vehicle weight

Gross vehicle wheel base

Gross vehicle width

If the level of tension in the belt is too high, it can result in a loss of power or in bending of the rotating shaft or crankshaft.

Correct

Incorrect

The coefficient of friction for the clutch facing is approximately

0.8

1.2

0.1

0.4

The most commonly used supplementary restraint system (SRS) component is

Airbag

Steering

Brake

Seat belt

In a fuel injection system, the electronic control module (ECM) calculates the optimum fuel-injection volume for the engine condition based on the data received from the sensors, and injects this volume of fuel into the intake manifold at the optimum timing.

Correct

Incorrect

In a spark plug, when the temperature of the central electrode exceeds a certain temperature, any carbon that has adhered will be burnt off, and the temperature at which this burning off carbon starts is referred to as the self cleaning temperature.

Correct

Incorrect

The natural gas is compressed in a CNG cylinder at a pressure of

250 bar

300 bar

220 bar

200 bar

The flywheel and the pressure plate bind the clutch disc between them so that the engine and the transmission can be engaged.

Yes

No

A baffle plate is fitted inside the oil pan to prevent the oil from splashing when it is subjected to vibration and other movement during vehicle operation.

False

True

Positive camber is used to compensate for wheels tilting inward due to the weight of the vehicle.

No

Yes

If the engine coolant leaks into the engine oil, then engine oil

Appears milky

Turns black

None of these

Becomes foamy

Which of the following symptom is caused as a result of brake disc run out?

Rapid wearing of the brake pads

Judder during braking

Ineffectiveness of the brakes

Localized wearing of the brake pads

A clutch is usually designed to transmit maximum torque which is

80 per cent of the maximum engine torque

None of these

150 per cent of the maximum engine torque

Equal to the maximum engine torque

The main function of intake manifold is that it

Promotes the mixture of air and fuel

Cools the intake air to a suitable temperature

Reduces intake noise

Distributes intake air equally to the cylinders

The diagram which shows the correct crank positions corresponding to the opening and closing of the valves, is known as

None of these

Indicator diagram

Axial force diagram

Valve timing diagram

The function of an alternator in an automobile is to

Convert mechanical energy into electrical energy

Partly convert engine power into electric power

Supply electric power

Continually recharge the battery

In axial flow compressor, exit flow angle deviation from the blade angle is a function of

Blade camber and incidence angle

Space-chord ratio

Blade camber and space-chord ratio

Blade camber

The increase in pressure in a roots blower is entirely due to back flow of air.

Disagree

Agree

A large clearance Volume in a reciprocating compressor results in

Increased volume flow rate

Lower delivery pressure

Lower suction pressure

Reduced volume flow rate

The actual volume of air delivered by a compressor, When reduced to the normal temperature and pressure conditions is called compressor capacity.

No

Yes