Dynamics of Machinery (3151911) MCQs

MCQs of Critical speeds of shafts

Showing 1 to 8 out of 8 Questions
1.

Critical speed is expressed as ______.

(a)

rotation of the shaft in degrees

(b)

rotation of the shaft in radians

(c)

rotation of the shaft in minutes

(d)

the natural frequency of the shaft

Answer:

Option (d)

2.

The factor which affects the critical speed of a shaft is

(a)

the diameter of the disc

(b)

the span of the shaft

(c)

eccentricity

(d)

all of the mentioned

Answer:

Option (d)

3.

The speed at which the shaft runs so that the additional deflection of the shaft from the axis of rotation becomes ___________ is known as critical or whirling speed.

(a)

zero

(b)

minimum

(c)

maximum

(d)

infinite

Answer:

Option (d)

4.

The critical speed may occur because of __________.

(a)

eccentric mounting of the rotor

(b)

non-uniform distribution of rotor material

(c)

bending of shaft

(d)

all of the mentioned

Answer:

Option (d)

5.

The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in

(a)

torsional vibrations

(b)

longitudinal vibrations

(c)

transverse vibrations

(d)

none of the mentioned

Answer:

Option (c)

6.

When the centre of gravity of the rotor lies between the centre line of the shaft and the centre line of the bearing, e is taken as positive.

(a)

True

(b)

False

Answer:

Option (b)

7.

The first critical speed of an automobile running on a sinusoidal road is calculated by ______.

(a)

resonance

(b)

approximation

(c)

superposition

(d)

rayleigh quotient

Answer:

Option (a)

8.

A shaft supported in ball bearings is assumed to be simply supported.

(a)

True

(b)

False

Answer:

Option (a)

Showing 1 to 8 out of 8 Questions