SECTION-7

MACHINE DESIGN MCQ

 

Q21. Which one of the following pairs is not correctly matched?

(a) Positive drive …… Belt drive 
(b) High velocity ratio …… Worm gearing 
(c) To connect non-parallel and non-intersecting shafts …… spiral gearing 
(d) Diminished noise and smooth operation …… Helical gears.                              (IES 1995)

Ans:(a) Positive drive …… Belt drive

 

Q22. A cold rolled steel shaft is designed on the basis of maximum shear stress theory. The rincipal stresses induced at its critical section are 60 MPa and –60 MPa respectively. If the yield stress for the shift material is 360 MPa, the factor of safety of the design is

(a) 2 
(b) 3 
(c) 4 
(d) 6. 

Ans:(b) 3

Q23. A 50 kW motor using six V-belts is used in a pulp mill. If one of the belts breaks after a month of continuous running, then

(a) the broken belt is to be replaced by a similar belt 
(b) all the belts are to be replaced 
(c) the broken belt and two adjacent belts are to be replaced 
(d) the broken belt and one adjacent belt is to be replaced                             (IAS 1994)

Ans:(b) all the belts are to be replaced

 

Q24. The bolts in a rigid flanged coupling connecting two shafts transmitting power are subjected to

(a) shear force and bending moment 
(b) axial force 
(c) torsion and bending moment 
(d) torsion.

Ans:(a) shear force and bending moment

 

Q25. Two shafts, one solid and the other hollow, of the same material will have the same strength if they are having

(a) same length and weight 
(b) same length and same polar modulus 
(c) same weight and same polar modulus 
(d) same length, weight and polar modulus.

Ans:(b) same length and same polar modulus

 

Q26. In the case of a flywheel, the maximum fluctuation of energy is the

(a) sum of maximum and minimum energies 
(b) difference between the maximum and minimum energies 
(c) ratio of maximum and minimum energy 
(d) ratio of minimum and maximum energy.                                      (IES 1998)

Ans:(b) difference between the maximum and minimum energies

 

Q27. Yield point in fatigue loading as compared to static loading, is

(a) higher 
(b) lower 
(c) same 
(d) none of the above. 

Ans:(b) lower

 

Q28. The basic load rating of a ball bearing is

(a) the maximum static radial load that can be applied without causing any plastic deformation of bearing components. 
(b) the radial load at which 90% of the group of apparently identical bearings run for 1 million revolutions before the first evidence of failure. 
(c) the maximum radial load that can be applied during operation without any plastic deformation of bearing components. 
(d) a combination of radial and axial loads that can be applied without any plastic deformation.

Ans:(b) the radial load at which 90% of the group of apparently identical bearings run for 1 million revolutions before the first evidence of failure.

 

Q29. If a shaft made from ductile material is subjected to combined bending and twisting moments, calculations based on which one of the following failure theories would give the most conservative value?

(a) Maximum principal stress theory 
(b) Maximum shear stress theory 
(c) Maximum strain energy theory 
(d) Maximum distortion energy theory.                                                 (IES 1996)

Ans:(d) Maximum distortion energy theory.

 

Q30. If the tearing efficiency of a riveted joint is 75 per cent, then the ratio of rivet hole diameter to the pitch is equal to

(a) 0.2 
(b) 0.25 
(c) 0.50 
(d) 0.60.                                                                                         (GATE 1996)

Ans:(b) 0.25

 

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Read More Sections of Machine Design

Each section contains maximum 80 Questions. To practice more questions visit other sections.
 

Machine Design MCQ – Section-1

 

Machine Design MCQ – Section-2

 

Machine Design MCQ – Section-3

 

Machine Design MCQ – Section-4

 

Machine Design MCQ – Section-5

 

Machine Design MCQ – Section-6

 

Machine Design MCQ – Section-7

 

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