371. In a boundary lubricated bearing, there is a __________ of lubricant between the journal and the bearing.
thick film
thin film
✅ The correct answer is option B.
Machine Design MCQs
372. A jam nut is a locking device in which
a thinner nut is tightened down over a thicker or main nut and the main nut is tightened against the thinner nut by loosening
a slot is cut in line with the centre of each face and a split pin passes through two slots in the nut and a hole in the bolt, so that a positive lock is obtained unless the pin shears
a slot is cut about half way through the nut and a small screw is tightened between the nut and the bolt in order to produce more friction
the bottom cylindrical
✅ The correct answer is option A.
373. According to maximum shear stress theory, the maximum shear stress in the shaft is
✅ The correct answer is option A.
374. A locking device extensively used in automobile industry is a
jam nut
castle nut
sawn nut
ring nut
✅ The correct answer is option B.
375. An elastic bar is fixed at the upper end and loaded at the lower end by a falling weight. The shock load produced can be reduced by
increasing the length of bar
decreasing the cross-sectional area of the bar
decreasing the modulus of elasticity of the bar
all of the above
✅ The correct answer is option D.
376. The shear stress at a point in a shaft subjected to a torque is
directly proportional to the polar moment of inertia and to the distance of the point from the axis
directly proportional to the applied torque and inversely proportional to the polar moment of inertia
directly proportional to the applied torque and the polar moment of inertia
inversely proportional
✅ The correct answer is option B.
378. According to Indian standards, a bolt thread of 6 mm size of coarse pitch and with allowance on the threads and normal tolerance grade is designated as
M6
M8
M6 – 8d
M8 – 6d
✅ The correct answer is option C.
379. In cylindrical cams, the follower moves
in a direction perpendicular to the cam axis
in a direction parallel to the cam axis
in any direction irrespective of cam axis
along the cam axis
✅ The correct answer is option B.
380. A metal pipe of 1 m diameter contains a fluid having a pressure of 1 N/mm2. If the permissible tensile stress in the metal is 20 N/mm2, then the thickness of the metal required for making the pipe will be
5 mm
10 mm
15 mm
25 mm
✅ The correct answer is option D.