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Gtu MCQ: Dynamics of Machinery (3151911)

The document contains 8 multiple choice questions about critical speeds of shafts. It discusses topics like what critical speed is expressed as, factors that affect critical speed of a shaft, when critical speed occurs, and assumptions made about shafts supported by ball bearings. The questions are from a GTU MCQ exam on Dynamics of Machinery.

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196 views2 pages

Gtu MCQ: Dynamics of Machinery (3151911)

The document contains 8 multiple choice questions about critical speeds of shafts. It discusses topics like what critical speed is expressed as, factors that affect critical speed of a shaft, when critical speed occurs, and assumptions made about shafts supported by ball bearings. The questions are from a GTU MCQ exam on Dynamics of Machinery.

Uploaded by

kannu19802550
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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GTU MCQ

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)
GTU MCQ
8. A shaft supported in ball bearings is assumed to be simply supported.
Dynamics of Machinery (3151911)  MCQs
(a) True
(b) False

Answer: Option (a)

Showing 1 to 8 out of 8 Questions

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