Engineering Mechanics MCQ Objective Question and Answers Part 3

Engineering Mechanics Multiple Choice Questions / Objectives Mechanical Questions and Answers

Engineering Mechanics MCQ : Part 1 | Part 2 | Part 3 | Part 4

63. If a suspended body is struck at the center of percussion, then the pressure on die axis passing through the point of suspension will be
(a) maximum
(b) minimum
(c) zero
(d) infinity
(e) same as the force applied.
Ans: c

65. The resultant of the following three couples 20 kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m arm, – ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be
(a) 20 kg, – ve sense
(b) 20 kg, + ve sense
(c) 10 kg, + ve sense
(d) 10 kg, – ve sense
(e) 45 kg, + ve sense.
Ans: a

68. Angle of friction is the
(a) angle between normal reaction and the resultant of normal reaction and the limiting friction
(b) ratio of limiting friction and normal reaction
(c) the ratio of minimum friction force to the friction force acting when the body is just about to move
(d) the ratio of minimum friction force to friction force acting when the body is in motion
(e) ratio of static and dynamic friction.
Ans: a

69. The coefficient of friction depends on
(a) area of contact
(b) shape of surfaces
(c) strength of surfaces
(d) nature of surface
(e) all of the above.
Ans: d

70. Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction
(a) along the plane
(b) horizontally
(c) vertically
(d) at an angle equal to the angle of friction to the inclined plane
(e) unpredictable.
Ans: d

71. The ratio of limiting friction and normal reaction is known as
(a) coefficient of friction
(b) angle of friction
(c) angle of repose
(d) sliding friction
(e) friction resistance.
Ans: a

72. Which one of the following statements is not correct
(a) the tangent of the angle of friction is equal to coefficient of friction
(b) the angle of repose is equal to angle of friction
(c) the tangent of the angle of repose is equal to coefficient of friction
(d) the sine of the angle of repose is equal to coefficient to friction
(e) none of the above.
Ans: d

73. On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be
(a) towards the wall at its upper end
(b) away from the wall at its upper end
(c) upwards at its upper end
(d) downwards at its upper end
(e) none of the above.
Ans: c

74. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be
(a) downwards at its upper end
(b) upwards at its upper end
(c) perpendicular to the wall at its upper end
(d) zero at its upper end
(e) none of the above.
Ans: d

76. Frictional force encountered after commencement of motion is called
(a) post friction
(b) limiting friction
(c) kinematic friction
(d) frictional resistance
(e) dynamic friction.
Ans: e

77. Coefficient of friction is the
(a) angle between normal reaction and the resultant of normal reaction and the limiting friction
(b) ratio of limiting friction and normal reaction
(c) the friction force acting when the body is just about to move
(d) the friction force acting when the body is in motion
(e) tangent of angle of repose.
Ans: b

78. Pick up wrong statement about friction force for dry surfaces. Friction force is
(a) proportional to normal load between the surfaces
(b) dependent on the materials of contact surface
(c) proportional to velocity of sliding
(d) independent of the area of contact surfaces
(e) none of the above is wrong statement.
Ans: c

79. A body of weight W on inclined plane of a being pulled up by a horizontal force P will be on the point of motion up the plane when P is equal to
(a) W
(b) W sin (a + $)
(c) Wtan(a + <|))
(d) W\an(a-<t>)
(e) Wtana.
Ans: c

80. A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t2 (t – 4), the acceleration of the particle will be given by the equation
(a) 3t2-lt
(b) 3t2+2t
(c) 6f-8
(d) 6f-4
(e) 6t2-8t.
Ans: c

81. If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella
(a) more inclined when moving
(b) less inclined when moving
(c) more inclined when standing
(d) less inclined when standing
(e) none of the above.
Ans: d

86. A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is
(a) 0°
(b) 30°
(c) 45°
(d) 60°
(e) 90°.
Ans: c

88. Limiting force of friction is the
(a) tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction
(b) ratio of limiting friction and normal reaction
(c) the friction force acting when the body is just about to move
(d) the friction force acting when the body is in motion
(e) minimum force of friction.
Ans: c

89. Coulomb friction is the friction between
(a) bodies having relative motion
(b) two dry surfaces
(c) two lubricated surfaces
(d) solids and liquids
(e) electrically charged particles.
Ans: a

90. Dynamic friction as compared to static friction is
(a) same
(b) more
(c) less
(d) may be less of more depending on nature of surfaces and velocity
(e) has no correlation.
Ans: c

Engineering Mechanics MCQ : Part 1 | Part 2 | Part 3 | Part 4