Mechanical Engineering Quiz # 15

When a column is subjected to an eccentric load, the stress induced in the column will be

Direct and bending stress both

Direct stress only

Shear stress only

Bending stress only

The rectangular beam 'A' has length l, width b and depth d. Another beam 'B' has the same length and depth but width is double that of 'A'. The elastic strength of beam 'B' will be __________ as compared to beam A.

Same

Double

Six times

Four times

The maximum stress produced in a bar of tapering section is at

Anywhere

Middle

Larger end

Smaller end

The point of contraflexure is a point where

Bending moment changes sign

Bending moment is maximum

Shear force is maximum

Shear force changes sign

When a rectangular beam is loaded transversely, the maximum compressive stress is developed on the

Top layer

Every cross-section

Bottom layer

Neutral axis

The limit of eccentricity is based upon no tension condition.

True

False

The dynamic friction is the friction experienced by a body, when the body

Is in motion

Just begins to slide over the surface of the other body

None of these

Is at rest

The acceleration of the particle moving with simple harmonic motion is inversely proportional to the displacement of the particle from the mean position.

No

Yes

A pair of friction discs is an example of rolling pair.

False

True

A disturbing mass m1 attached to the rotating shaft may be balanced by a single mass m2 attached in the same plane of rotation as that of m1, such that (where r1 and r2 are the radii of rotation of m1 and m2 respectively)

M1m2 = r1r2

M1r1 = m2r2

None of these

M1r2 = m2r1

When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be

Stable

Isochronous

Unstable

None of these

In order to balance the reciprocating masses,

Secondary forces and couples must be balanced

Both primary forces and couples must be balanced and secondary forces and couples must be balanced

None of these

Primary forces and couples must be balanced

An automobile steering gear is an example of

Rolling pair

Lower pair

Sliding pair

Higher pair

The gears are termed as medium velocity gears, if their peripheral velocity is

1 - 3 m/s

15 - 30 m/s

30 - 50 m/s

3 - 15 m/s

In order to give the primary balance of the reciprocating parts of a multi-cylinder in-line engines,

Both the algebraic sum of the primary forces must be equal to zero and the algebraic sum of the couples about any point in the plane of the primary forces must be equal to zero

None of these

The algebraic sum of the primary forces must be equal to zero

The algebraic sum of the couples about any point in the plane of the primary forces must be equal to zero

The factor which affects the critical speed of a shaft is

All of these

Diameter of disc

Span of shaft

Eccentricity

In a coupling rod of a locomotive, each of the four pairs is a __________ pair.

Sliding

Rolling

Turning

Screw

Whitworth quick return motion mechanism consists of three turning pairs and one sliding pair.

Right

Wrong

When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a

Force-closed pair

Lower pair

Self-closed pair

Higher pair

The static friction

Is independent of the area of contact, between the two surfaces

All of these

Always acts in a direction, opposite to that in which the body tends to move

Bears a constant ratio to the normal reaction between the two surfaces

Which of the following is a turning pair?

Piston and cylinder of a reciprocating steam engine

Ball and a socket joint

Lead screw of a lathe with nut

Shaft with collars at both ends fitted into a circular hole

The pair is known as a higher pair, when the relative motion between the elements of a pair is

Partly turning and partly sliding

Sliding only

Turning only

Rolling only

The maximum fluctuation of energy is the

Ratio of the mean resisting torque to the workdone per cycle

Difference between the maximum and minimum energies

Variations of energy above and below the mean resisting torque line

Sum of the maximum and minimum energies

The cam follower generally used in automobile engines is

Spherical faced follower

Fiat faced follower

Knife edge follower

Roller follower

The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)

(1 - c)m.ω2.r(cos θ - sin θ)

C.m.ω2.r sin θ

M.ω2.r cos θ

M.ω2.r(cos θ - sin θ)

In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to

0.4

0.8

0.6

0.2

According to Gay-Lussac law for a perfect gas, p/T = constant, if v is kept constant.

True

False

All the commercial liquid fuels are derived from natural petroleum (or crude oil).

True

False

Which of the following has the minimum atomic mass?

Carbon

Sulphur

Oxygen

Nitrogen

The compression ratio for petrol engines is

3 to 6

20 to 30

5 to 8

15 to 20

Quiz:	Mechanical Engineering Quiz # 15
Subject:	Strength Of Materials
Total Questions:	1465 MCQs
Time:	1465 Minutes