Q71. The type of gear used to keep noise minimum, should be

(a) cycloidal 
(b) involute 
(c) bevel 
(d) helical. 

Ans:(d) helical.


Q72. The cracks due to fatigue spreads only by

(a) tensile stress along its direction 
(b) compressive stress along its direction 
(c) shear stress 
(d) tensile stress and in direction perpendicular to the tensile stress. 

Ans:(d) tensile stress and in direction perpendicular to the tensile stress.


Q73. A spring material should have the following properties

(a) high yield strength 
(b) more hardness 
(c) high breaking strength 
(d) all of the above 

Ans:(d) all of the above


Q74. Maximum shear stress developed on the surface of a solid circular shaft under pure torsion is 240 MPa. If the shaft diameter is doubled, then the maximum shear stress developed corresponding to the same torque is

(a) 120 MPa 
(b) 60 MPa  
(c) 30 MPa 
(d) 15 MPa.                                                                                                      (GATE 2003)

Ans:(c) 30 MPa


Q75. The ratio of maximum stress (at a notch or a fillet) in a machine to the nominal stress at the same section, is known as

(a) endurance limit 
(b) stress concentration factor 
(c) surface finish factor 
(d) factor of safety. 

Ans:(b) stress concentration factor


Q76. The design calculations for members subjected to fluctuating loads with the same factor of safety yield the most conservative estimates when using

(a) Gerber relation 
(b) Soderberg relation 
(c) Goodman relation 
(d) None of the above.                                                                                   (IES 1995)

Ans:(b) Soderberg relation


Q77. A transmission shaft subjected to bending loads must be designed on the basis of

(a) maximum normal stress theory 
(b) maximum shear stress theory 
(c) maximum normal stress and maximum shear stress theories 
(d) fatigue strength.                                                                                   (IES 1995)

Ans:(c) maximum normal stress and maximum shear stress theories


Q78. A shaft can safety transmit 90 kW while rotating at a given speed. If this shaft is replaced by a shaft of diameter double of the previous one and rotated at half the speed of the previous, the power that can be transmitted by the new shaft is

(a) 90 kW 
(b) 180 kW 
(c) 360 kW 
(d) 720 kW. 

Ans:(a) 90 kW


Q79. When compared to a rod of same diameter and material, a wire rope

(a) is less flexible 
(b) has a much smaller load carrying capacity 
(c) does not provided much warning before failure 
(d) provides much greater time for remedial action before failure.                                  (IES 1994)

Ans:(d) provides much greater time for remedial action before failure


Q80. A solid circular shaft is subjected to a maximum shear stress of 140 MPa. The magnitude of the maximum normal stress developed in the shaft is

(a) 140 MPa 
(b) 80 MPa 
(c) 70 MPa 
(d) 60 MPa.                                                                            (IAS 1995)


Ans:(a) 140 MPa

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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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