Category: ENGINEERING MECHANICS Questions and Answers

140 TOP ENGINEERING MECHANICS Objective Questions and Answers :- <—- CLICK HERE

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

(a) newton
(b) pascal
(c) kilogram meter
(d) watt
(e) joule.
Ans: e

(a) kcal
(b) kg m
(c) kWhr
(d) hp
(e) hp hr.
Ans: d

(a) the floor is smooth, the wall is rough
(b) the floor is rough, the wall is smooth
(c) the floor and wall both are smooth surfaces
(d) the floor and wall both are rough surfaces
(e) will be in equilibrium under all conditions.
Ans: c

140 TOP ENGINEERING MECHANICS Multiple Choice Questions pdf :- <—–CLICK HERE

91. Tangent of angle of friction is equal to
(a) kinetic friction
(b) limiting friction
(c) angle of repose
(d) coefficient of friction
(e) friction force.
Ans: d

92. Kinetic friction is the
(a) tangent of 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) dynamic friction.
Ans: d

95. The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to
(a) Wtan(a + <)>)
(b) Wtan(a-<)>)
(c) Wcos(a + <t>)
(d) Wsin(a + <(>)
(e) W (sin a + cos <j>).
Ans: a

96. A semi-circular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi-cricular disc and horizontal surface is i. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will
(a) remain horizontal
(b) slant up towards direction of pull
(c) slant down towards direction of pull
(d) unpredictable
(e) none of the above.
Ans: c

97. A particle inside a hollow sphere of radius r, having coefficient of friction -rr can rest upto height of
(a) r/2
(b) r/A
(c) r/%
(d) 0.134 r
(e) 3r/8.
Ans: d

98. The algebraic sum of moments of the forces forming couple about any point in their plane is
(a) equal to the moment of the couple
(b) constant
(c) both of above are correct
(d) both of above are wrong
(e) none of the above.
Ans: a

99. A single force and a couple acting in the
same plane upon a rigid body
(a) balance each other
(b) cannot balance each other
(c) produce moment of a couple
(d) are equivalent
(e) none of the above.
Ans: b

100. If three forces acting in one plane upon a rigid body, keep it in equilibrium, then they must either
(a) meet in a point
(b) be all parallel
(c) at least two of them must meet
(d) all the above are correct
(e) none of the above.
Ans: d

(a) kilogram
(b) newton
(c) watt
(d) dyne
(e) joule.
Ans: b