machine design MCQs – Page 3

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

machine design Mcqs
41. Which process will increase the fatigue duration of parts ?
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A. decarburisation

B. electroplating

C. shot-peening

D. all of the above.

E. finishing and polishing

42. The pitch of threads on a Jock nut in comparison to pitch of nut is_________________?
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A. very fine

B. same

C. very coarse

D. coarser

E. finer

43. If an unsupported uniform cross sectional elastic bar is subjected to a longitudinal impact from a rigid bob moving with velocity v, then a compressive wave of intensity sc is propagated through the bar as follows______________________?
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A. none of the above, where E = modulus of elasticity and p = mass density

B. vVvF

C. WpE/2

D. vpE

E. IvHpE

44. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test_________________?
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A. Vicker

B. Shores sceleroscope

C. Rockwell

D. Brinell

E. none of the above

45. Eye bolts are used for_________________?
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A. transmission of power

B. absorbing shock and vibrations

C. foundation purposes

D. locking devices *

E. lifting and transportation of machines and cubicles
46. Stress concentration in cyclic loading is more serious in__________________?
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A. ductile materials

B. brittle materials

C. equally serious in both cases

D. depends on other factors

E. unpredictable

47. The draw of cotter need not exceed_________________?
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A. 25 mm

B. 10 mm

C. 20 mm

D. 5 mm

E. 3 mm
48. The connecting rod bolts are tightened up with initial tension greater than the external load so that___________________?
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A. bolts are weakest elements

B. bolts will not loosen during service

C. joint may not open up

D. the resultant load on the bolt would not be affected by the external cyclic load

E. none of the above

49. In cross or regular lay ropes_________________?
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A. wires are not twisted

B. wires in two adjacent strands are twisted in opposite direction

C. direction of twist of wires and strands are same

D. direction of twist of wires in strands is opposite to the direction of twist of strands

E. none of the above

50. Cold working________________?
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A. decreases the fatigue strength

B. increases the fatigue strength

C. none of the above

D. alone has no influence on fatigue strength

E. has no influence on fatigue strength

51. The endurance limit of a material with finished surface in comparison to rough surface is_________________?
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A. more or less depending on quantum of load

B. more

C. less

D. unpredictable

E. same

52. At low temperatures (say 75C) the notched-bar impact value of steel____________________?
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A. depends on heat treatment carried out

B. none of the above

C. remains same

D. decreases markedly

E. increases markedly

53. Applications in which stresses are encountered in one direction only uses following type of threads____________________?
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A. BSW

B. metric

C. square

D. buttress

E. acme

54. Oil in journal bearing should be applied at the point where load is________________?
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A. maximum

B. unpredictable

C. average

D. nil or lightest

E. any one of the above

55. The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80 for_________________?
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A. reducing stress concentration

B. all of the above

C. safety

D. ease of manufacture

E. fullering and caulking
56. The connecting rod bolts are tightened up so that tightening stress _________________?
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A. is about yield point divided by safety factor

B. none of the above

C. approaches yield point

D. is just sufficient to hold parts together

E. is 50% of yield point

57. Resistance to fatigue of a material is measured by________________?
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A. Youngs modulus

B. endurance limit

C. ultimate tensile strength

D. elastic limit

E. coefficient of elasticity

58. The valve rod in a steam engine is connected to an eccentric rod by_________________?
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A. universal coupling

B. kunckle joint

C. gib and cotter joint

D. cotter joint

E. bolted joint

59. Fatigue strength can be increased by__________________?
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A. cold working

B. hot working

C. shot peening

D. using gradual changes of section

E. grinding and lapping surface

60. If d is the diameter of bolt hole then for a flanged pipe joint to be leak proof, the circumferential pitch of the bolts should be_________________?
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A. 20Vdto30Vd

B. 30V5?to40Vd

C. lOVZ

D. 10VZtol5Vd

E. 15Vdto20VZ