Machine Design Questions And Answers Objective Type

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Machine Design MCQ

SET-5


81. When a shaft is subjected to combined twisting moment (T) and bending moment (M), then the equivalent twisting moment is equal to


Answer: B

82. In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.

  • A. right hand
  • B. left hand

Answer: B

83. A connecting rod is designed as a

  • A. long column
  • B. short column
  • C. strut
  • D. all of these

84. The cross-section of the arm of a bell crank lever is

  • A. rectangular
  • B. elliptical
  • C. I-section
  • D. any one of these

Answer: D


85. The rocker arms in internal combustion engines are of first type levers.

  • A. Correct 
  • B. Incorrect

Answer: A

86. In a crossed belt drive, the shafts are arranged parallel and rotate in the same directions.

  • A. Correct 
  • B. Incorrect

Answer: B

87. In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as

  • A. helix angle
  • B. pressure angle
  • C. pitch lead angle
  • D. none of these

Answer: A


88.  Idler pulley is used for

  • A. increasing velocity ratio
  • B. for applying tension
  • C. changing the direction of motion of belt
  • D. all of these

Answer: B

89. The bell crank levers used in railway signalling arrangement are of third type levers.

  • A. True 
  • B. False

Answer: B


90.  When spring index increases, the value of Wahl’s stress factor

  • A. increases linearly
  • B. decreases linearly
  • C. remains same
  • D. increases exponentially

Answer: D


91.  A shaft is subjected to a maximum bending stress of 80 N/mm2 and maximum shearing stress equal to 30 N/mm2 at a particular section. If the yield point in tension of the material is 280 N/mm2 and the maximum shear stress theory of failure is used, then the factor of safety obtained will be

  • A. 2.5 
  • B. 2.8
  • C. 3.0 
  • D. 3.5

Answer: B

92. The longitudinal stress is __________ of the circumferential stress.

  • A. one-half 
  • B. two-third
  • C. three-fourth 
  • D. double

Answer: A


93.  The expression 0.175 – 0.841/T is the Lewis form factor for

  • A.  2°composite and full depth involute system
  • B. 20° full depth involute system
  • C. 20° stub system
  • D. none of the above

Answer: C

94. A screw will be self locking, if

  • A. friction angle is less than helix angle
  • B. friction angle is more than helix angle
  • C. friction angle is equal to helix angle
  • D. efficiency of screw is 100%

Answer: B


95. The maximum shear stress theory is used for

  • A. brittle materials
  • B. ductile materials
  • C. plastic materials
  • D. non-ferrous materials

Answer: B


96. The elasticity is the property of a material which enables it to

  • A. regain its original shape after deformation when the external forces are removed
  • B. draw into wires by the application of a tensile force
  • C. resist fracture due to high impact loads
  • D. retain deformation produced under load permanently

Answer: A

97. The surface finish factor for a mirror polished material is

  • A. 0.45 
  • B. 0.65
  • C. 0.85 
  • D. 1

Answer: D


98.  For low and moderate speed engines, the cam follower should move with

  • A. uniform velocity
  • B. simple harmonic motion
  • C. uniform accleration and retardation
  • D. cycloidal motion

Answer: B

99. Which of the following statement is correct ?

  • A. A parallel sunk key is a taperless key
  • B. A parallel sunk key may be rectangular or square in cross-section
  • C. A flat saddle key is a taper key which fits in a key way of the hub and is flat on the shaft
  • D. all of the above

Answer: D

100.  When a bolt and nut is made of mild steel, then the effective height of nut is made equal to (where d = Nominal diameter of bolt)

  • A. 0.5 d
  • B. 0.75 d
  • C. d
  • D. 1.25 d

Answer: C

 

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