machine design MCQs – Page 5

Practise focused machine design questions with marked answers for exam preparation and subject revision.

machine design Mcqs
81. Stress concentration in static loading is_________________?
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A. ch is correct statement ?

82. Machine screws are________________?
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A. used to prevent relative motion be-tween two parts

B. none of the above

C. similar to stud

D. slotted for a screw driver and generally used with a nut

E. similar to small size tap bolts except that a greater variety of shapes of heads are available

83. In order to avoid tearing of the plate at edge, the distance from the center line of the rivet hole to the nearest edge of the plate in terms of dia of rivet d should be equal to__________________?
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A. 1.75 d

B. 2 d.

C. 1.5 d

D. d

E. 1.25 d

84. The shearing stresses in the inner face as compared to outer face of the wire in a heavy close coiled spring is_________________?
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A. larger

B. equal

C. smaller

D. larger/smaller depending on diameter of spring coil

E. unpredictable

85. If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation_______________?
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A. 138 d

B. 168 d

C. 151 d

D. 124 d

E. 102 d

86. When two springs are in series (having stiffness K), the equivalent stiffness will be________________?
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A. 2K

B. UK

C. K/2

D. KIA

E. K

87. Spring stiffness is__________________?
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A. its capability of storing energy

B. ratio of coil diameter to wire diameter

C. none of the above

D. its ability to absorb shocks

E. load required to produce unit deflection
88. If shearing stress in nut is half the tensile stress in a bolt, then nut length should be equal to___________________?
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A. 1.25 x diameter of bolt

B. 1.5 x diameter of bolt

C. diameter of bolt

D. 0.5 x diameter of bolt

E. 0.75 x diameter of bolt

89. In the case of an elastic bar fixed at upper end and loaded by a falling weight at lower end, the shock load produced can be decreased by_________________?
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A. would depend upon other factors

B. decreasing the cross-section area of bar

C. increasing the cross-section area of bar

D. remain unaffected with cross-section area

E. none of the above

90. In Vickers hardness testing, the pyramid indentor apex is__________________?
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A. 40

B. 122

C. 152

D. 136

E. 161.

91. Rankines theory of failure is applicable for following type of materials___________________?
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A. ductile

B. tough

C. brittle

D. plastic

E. elastic

92. The edges of a boiler plate are bevelled to an angle of______________?
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A. 60

B. 45

C. 85.

D. 30

E. 80
93. In oilness bearings________________?
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A. grease required to be applied after some intervals

B. do not require external supply of lubricant

C. the oil film pressure is generated only by the rotation of the journal

D. none of the above

E. the oil film is maintained by supplying oil under pressure

94. Resilience of a material is important, when it is subjected to________________?
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A. combined loading

B. thermal stresses

C. fatigue

D. shock loading

E. wear and tear

95. For tight leakage joints, following type of thread is best suited ____________________?
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A. square

B. buttress

C. NPT (national pipe threads)

D. metric

E. acme

96. The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is___________________?
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A. 1 micron

B. 0.1 micron

C. 10 microns

D. 25 microns

E. 0.01 micron

97. Yield point in fatigue loading as compared to static loading is__________________?
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A. same

B. depends on other factors

C. lower

D. none of the above

E. higher

98. The included angle in unified of American National threads is___________________?
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A. 29

B. 47

C. none of the above

D. 60

E. 55

99. In order to permit the thermal expansion/contraction of tubing, it should be______________?
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A. honed

B. crimped

C. bent

D. none of the above

E. flared

100. If two springs are in parallel then their overall stiffness will be_______________?
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A. double

B. none of the above

C. unpredictable

D. same

E. half