Mechanical Engineering-Engineering Mechanics MCQ PDF

1. The unit of force in S.I. units is
(a) kilogram
(b) newton
(c) watt
(d) dyne
(e) joule.
Ans: b

2. The unit of work or energy in S.I. units
is
(a) newton
(b) pascal
(c) kilogram meter
(d) watt
(e) joule.
Ans: e

3. The unit of power in S.I. units is
(a) newton meter
(b) watt
(c) joule
(d) kilogram meter/sec.
(e) pascal per sec.
Ans: b

4. Forces are called concurrent when their
lines of action meet in
(a) one point      
(b) two points
(c) plane
(d) perpendicular planes
(e) different planes.
Ans: a

5. Forces are called coplanar when all of
them acting on body lie in
(a) one point      
(b) one plane
(c) different planes
(d) perpendicular planes
(e) different points.
Ans: b

6. A force acting on a body may
(a) introduce internal stresses
(b) balance the other forces acting on it
(c) retard its motion
(d) change its motion
(e) all of the above.
Ans: e

7. Which is the correct statement about law
of polygon of forces ?
(a) if any number of forces acting at a point can be represented by the sides
of a polygon taken in order, then the forces are in equilibrium
(b) if any number of forces acting at a point
can be represented in direction and magnitude by the sides of a polygon, then
the forces are in equilibrium
(c) if a polygon representing forces acting
at a point is closed then forces are in equilibrium
(d) if any number of forces acting at a point
can be represented in direction and magnitude by the sides of a polygon taken
in order, then the forces are in equilibrium
(e) none of the above.
Ans: d

8. Effect of a force on a body depends upon
(a) magnitude
(b) direction
(c) position or line of action
(d) all of the above
(e) none of the above.
Ans: d

9. If a number of forces act simultaneously
on
a particle, it is possible
(a) not a replace them by a single force
(b) to replace them by a single force
(c) to replace them by a single force through
C.G.
(d) to replace them by a couple
(e) to replace them by a couple and a force.
Ans: b

11. A force is completely defined when we
specify
(a) magnitude
(b) direction
(c) point of application
(d) all of the above
(e) none of the above.
Ans: d

12. If two equal forces of magnitude P act at
an angle 9°, their resultant will be
(a) P/2 cos 9/2
(b) IP sin 9/2
(c) 2P tan 9/2
(d) IP cos 9/2
(e) Psin 9/2.
Ans: d

13. The algebraic sum of the resolved parts
of a number of forces in a given direction is equal to the resolved part of
their resultant in the same direction. This is as per the principle of
(a) forces
(b) independence of forces
(c) dependence of forces
(d) balance of force
(e) resolution of forces.
Ans: e

14. The resolved part of the resultant of two
forces inclined at an angle 9 in a given direction is equal to
(a) the algebraic sum of the resolved parts
of the forces in the given direction
(b) the sum of the resolved parts of the
forces in the given direction
(c) the difference of the forces multiplied
by the cosine of 9
(d) the sum of the forces multiplied by the
sine of 9
(e) the sum of the forces multiplied by the
tangent of 9.
Ans: a

15. Which of the following do not have
identical dimensions ?
(a) Momentum and impulse
(b) Torque and energy
(c) Torque and work
(d) Kinetic energy and potential energy
(e) Moment of a force and angular momentum.
Ans: e

16. Which of the following is not the unit of
distance ?
(a) angstrom
(b) light year
(c) micron
(d) millimetre
(e) milestone.
Ans: e

17. Which of the following is not the unit of
power ?
(a) kW (kilowatt)
(b) hp (horse power)
(c) kcal/sec
(d) kg m/sec
(e) kcal/kg sec.
Ans: e

18. Which of the following is not the unit of
work, energy and heat ?
(a) kcal
(b) kg m
(c) kWhr
(d) hp
(e) hp hr.
Ans: d

19. Which of the following is not the unit of
pressure ?
(a) kg/cm
(b) ata
(c) atmosphere  
(d) mm of wcl
(e) newton.
Ans: e

20. The weight of a body is due to
(a) centripetal force of earth
(b) gravitational pull exerted by the earth
(c) forces experienced by body in atmosphere
(d) force of attraction experienced by
particles
(e) gravitational force of attraction towards
the center of the earth.
Ans: e

21. The forces, which meet at one point, but
their lines of action do not lie in a plane, are called
(a) coplanar non-concurrent forces
(b) non-coplanar concurrent forces
(c) non-coplanar non-concurrent forces
(d) intersecting forces
(e) none of the above.
Ans: b

22. When trying to turn a key into a lock,
following is applied
(a) coplanar force
(b) non-coplanar forces
(c) lever
(d) moment
(e) couple.
Ans: e

23. Which of the following is not a scalar
quantity
(a) time
(b) mass
(c) volume
(d) density
(e) acceleration.
Ans: e

24. According to principle of
transmissibility of forces, the effect of a force upon a body is
(a) maximum when it acts at the center of
gravity of a body
(b) different at different points in its line
of action
(c) the same at every point in its line of
action
(d) minimum when it acts at the C.G. of the
body
(e) none of the above.
Ans: c

25. Which of the following is a vector
quantity
(a) energy
(b) mass
(c) momentum  
(d) angle
(e) speed.
Ans: c

26. The magnitude of two forces, which when
acting at right angle produce resultant force  of VlOkg and when acting at
60° produce resultant of Vl3 kg. These forces are
(a) 2 and V6
(b) 3 and 1 kg
(c) V5andV5
(d) 2 and 5
(e) none of the above.
Ans: c

27. A number of forces acting at a point will
be in equilibrium if
(a) their total sum is zero
(b) two resolved parts in two directions at right angles are equal
(c) sum of resolved parts in any two
per-pendicular directions are both zero
(d) all of them are inclined equally
(e) none of the above.
Ans: c

28. Two non-collinear parallel equal forces
acting in opposite direction
(a) balance each other
(b) constitute a moment
(c) constitute a couple
(d) constitute a moment of couple
(e) constitute a resultant couple.
Ans: c

29. According to principle of moments
(a) if a system of coplanar forces is in equilibrium, then their algebraic sum
is zero
(b) if a system of coplanar forces is in equilibrium, then the algebraic sum of
their moments about any point in their plane is zero
(c) the algebraic sum of the moments of any
two forces about any point is equal to moment of theiwesultant about the same
point
(d) positive and negative couples can be
balanced
(e) none of the above.
Ans: b

30. Which of the following is not a vector quantity
(a) weight
(b) velocity
(c) acceleration  
(d) force
(e) moment.
Ans: a

31. According to law of triangle of forces
(a) three forces acting at a point will be in
equilibrium
(b) three forces acting at a point can be
represented by a triangle, each side being proportional to force
(c) if three forces acting upon a patticle
are represented in magnitude and direction by the sides of a triangle, taken in
order, they will be in equilibrium
(d) if three forces acting at a point are in
equilibrium, each force is proportional to the sine of the angle between the
other two
(e) none of the above.
Ans: c

33. If a rigid body is in equilibrium under the action of three forces, then
(a) these forces are equal
(b) the lines of action of these forces meet
in a point
(c) the lines of action of these forces are
parallel
(d) (b) and (c) above
(e) none of the above.
Ans: d

34. D’ Alembert’s principle is used for
(a) reducing the problem of kinetics to
equivalent statics problem
(b) determining stresses in the truss
(c) stability of floating bodies
(d) designing safe structures
(e) solving kinematic problems.
Ans: a

35. A heavy ladder resting on floor and
against a vertical wall may not be in equilibrium, if
(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

38. According to Lami’s theorem
(a) three forces acting at a point will be in
equilibrium
(b) three forces acting at a point can be
represented by a triangle, each side being proportional to force
(c) if three forces acting upon a particle
are represented in magnitude and
direction by the sides of a triangle, taken in order, they will be in
equilibrium
(d) if three forces acting at a point are in
equilibrium, each force is proportional to the sine of the angle between the
other two
(e) none of the above.
Ans: d

39. Two coplanar couples having equal and opposite moments
(a) balance each other
(b) produce a couple and an unbalanced force
(c) are equivalent
(d) produce a moment of couple
(e) can not balance each other.
Ans: e

40. A framed structure is perfect if it
contains members equal to
(a) 2n-3
(b) n-l
(c) ‘2n-l
(d) n – 2
(e) 3n-2.
where n = number of joints in a frame
Ans: a

42. The product of either force of couple
with the arm of the couple is called
(a) resultant couple
(b) moment of the forces
(c) resulting couple
(d) moment of the couple
(e) none of the above.
Ans: d

43. In detennining stresses in frames by
methods of sections, the frame is divided into two parts by an imaginary
section drawn in such a way as not to cut more than
(a) two members with unknown forces of the
frame
(b) three members with unknown forces of the
frame
(c) four members with unknown forces of the
frame
(d) three members with known forces of the
frame
(e) four members with two known forces.
Ans: b

44. The center of gravity of a uniform lamina
lies at
(a) the center of heavy portion
(b) the bottom surface
(c) the mid point of its axis
(d) all of the above
(e) none of the above.
Ans: c

45. Center of gravity of a solid cone lies on
the axis at the height
(a) one-fourth of the total height above base
(b) one-third of the total height above base
(c) one-half of the total height above base
(d) three-eighth of the total height above
the base
(e) none of the above.
Ans: a

46. Center of percussion is
(a) the point of C.G.
(b) the point of metacentre
(c) the point of application of the resultant
of all the forces tending to cause a body to rotate about a certain axis
(d) point of suspension
(e) the point in a body about which it can
rotate horizontally and oscillate under the influence of gravity.
Ans: c

47. Center of gravity of a thin hollow cone
lies on the axis at a height of
(a) one-fourth of the total height above base
(b) one-third of the total height above base
(c) one-half of the total height above base
(d) three-eighth of the total height above
the base
(e) none of the above.
Ans: b

48. The units of moment of inertia of an area
are
(a) kg m2
(b) m4
(c) kg/m2
(d) m3
(e) kg/m4.
Ans: b

49. The center of percussion of the
homogeneous rod of length L suspended at the top will be
(a) L/2
(b) L/3
(c) 3L/4
(d) 2L/3
(e) 3L/8.
Ans: d

50. The center of gravity of a triangle lies
at the point of
(a) concurrence of the medians
(b) intersection of its altitudes
(c) intersection of bisector of angles
(d) intersection of diagonals
(e) all of the above.
Ans: a

51. The units of moment of inertia of mass
are
(a) kg m2
(b) m4
(c) kg/m2
(d) kg/m
(e) m2/kg.
Ans: a

52. The possible loading in various members
of framed structures are
(a) compression or tension
(b) buckling or shear
(c) shear or tension
(d) all of the above
(e) bending.
Ans: a

53. A heavy string attached at two ends at
same horizontal level and when central dip is very small approaches the
following curve
(a) catenary
(b) parabola
(c) hyperbola    
(d) elliptical
(e) circular arc.
Ans: b

54. A trolley wire weighs 1.2 kg per meter
length. The ends of the wire are attached to two poles 20 meters apart. If the
horizontal tension is 1500 kg find the dip in the middle of the span
(a) 2.5 cm
(b) 3.0 cm
(c) 4.0 cm
(d) 5.0 cm
(e) 2.0 cm.
Ans: c

55. From a circular plate of diameter 6 cm is
cut out a circle whose diameter is a radius of the plate. Find the e.g. of the
remainder from the center of circular plate
(a) 0.5 cm
(b) 1.0 cm
(c) 1.5 cm
(d) 2.5 cm
(e) 0.25 cm.
Ans: a

58. Pick up the incorrect statement from the
following :
(a) The C.G. of a circle is at its center
(b) The C.G. of a triangle is at the intersection of its medians
(c) The C.G. of a rectangle is at the
inter-section of its diagonals
(d) The C.G. of a semicircle is at a distance
of r/2 from the center
(e) The C-G. of an ellipse is at its center.
Ans: d

59. The center of percussion of a solid
cylinder of radius r resting on a horizontal plane will be
(a) r/2
(b) 2r/3
(c) r/A
(d) 3r/2
(e) 3r/A.
Ans: d

62. In the equation of virtual work, following force is neglected
(a) reaction of any smooth surface with which
the body is in contact
(b) reaction of a rough surface of a body
which rolls on it without slipping
(c) reaction at a point or an axis, fixed in
space, around which a body is con-strained to turn
(d) all of the above
(e) none of the above.
Ans: d

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) Wan(a-)
(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

92. 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

93. 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 (a) Wtan(a + )
(b) Wtan(a-)
(c) Wcos(a + )
(d) Wsin(a + )
(e) W (sin a + cos ).
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

101. The maximum frictional force which comes
into play when a body just begins to slide over another surface is called
(a) limiting friction
(b) sliding friction
(c) rolling friction
(d) kinematic friction
(e) dynamic friction.
Ans: a

102. The co-efficient of friction depends
upon
(a) nature of surfaces
(b), area of contact
(c) shape of the surfaces
(d) ail of the above.
(e) (a) and (b) above.
Ans: a

104. The necessary condition for forces to be
in equilibrium is that these should be
(a) coplanar
(b) meet at one point ;
(c) both (a) and (b) above
(d) all be equal
(e) something else.
Ans: c

105. If three forces acting in different
planes can be represented by a triangle, these will be in
(a) non-equilibrium
(b) partial equilibrium
(c) full equilibrium
(d) unpredictable
(e) none of the above.
Ans: a

106. If n = number of members andy = number
of joints, then for a perfect frame, n =
(a) j-2
(b) 2j-l
(c) 2/-3
(d) 3/-2
(e) 2/ -4.
Ans: c

107. A body moves, from rest with a constant
acceleration of 5 m per sec. The distance covered in 5 sec is most nearly
(a) 38 m
(b) 62.5 m
(C) 96 m
(d) 124 m
(e) 240 m.
Ans: b

108. A flywheel on a motor goes from rest to
1000 rpm in 6 sec. The number of revolutions made is nearly equal to
(a) 25
(b) 50
(c) 100
(d) 250
(e) 500.
Ans: b

109. Which of the following is the locus of a
point that moves in such a manner that its distance from a fixed point is equal
to its distance from a fixed line multiplied by a constant greater than one
(a) ellipse
(b) hyperbola
(c) parabola
(d) circle
(e) none of the above.
Ans: b

111. Which of the following is not the unit
of energy
(a) kg m
(b) kcal
(c) wattr
(d) watt hours
(e) kg m x (m/sec)2.
Ans: c

112. A sample of metal weighs 219 gms in air,
180 gms in water, 120 gms in an unknown fluid. Then which is correct statement
about density of metal
(a) density of metal can’t be determined
(b) metal is twice as dense as water
(c) metal will float in water
(d) metal is twice as dense as unknown fluid
(e) none of the above.
Ans: a

113. The C.G. of a solid hemisphere lies on
the central radius 3r
(a) at distance — from the plane base 3r
(b) at distance — from the plane base 3r
(c) at distance — from the plane base 3r
(d) at distance — from the plane base or
(e) at distance — from the plane base.
Ans: d

117. The C.G. of a plane lamina will not be
at its geometrical centre in the case of a
(a) right angled triangle
(b) equilateral triangle
(c) square
(d) circle
(e) rectangle.
Ans: a

119. The C.G. of a right circular solid cone
of height h lies at the following distance from the base
(a) h/2
(b) J/3
(c) h/6
(d) h/4
(e) 3/i/5.
Ans: d

122. The M.I. of hollow circular section
about a central axis perpendicular to section as compared to its M.I. about
horizontal axis is
(a) same
(b) double
(c) half
(d) four times
(e) one fourth.
Ans: b

126. Which of the following is the example of
lever of first order
(a) arm of man
(b) pair of scissors
(c) pair of clinical tongs
(d) all of the above
(e) none of the above.
Ans: d

127. A pair of smith’s tongs is an example of
the lever of
(a) zeioth order
(b) first order
(c) second order
(d) third order
(e) fourth order.
Ans: c

128. In the lever of third order, load W,
effort P and fulcrum F are oriented as follows
(a) W between P and F
(b) F between W and P
(c) P between W and F
(d) W, P and F all on one side
(e) none of the above.
Ans: a

129. The angle which an inclined plane makes
with the horizontal when a body placed on it is about to move down is known as
angle of
(a) friction
(b) limiting friction
(c) repose
(d) kinematic friction
(e) static friction.
Ans: c

130. In actual machines
(a) mechanical advantage is greater than
velocity ratio
(b) mechanical advantage is equal to velocity
ratio
(c) mechanical advantage is less than
velocity ratio
(d) mechanical advantage is unity
(e) none of the above.
Ans: c

131. In ideal machines
(a) mechanical advantage is greater than
velocity ratio
(b) mechanical advantage is equal to velocity
ratio
(c) mechanical advantage is less than
velocity ratio
(d) mechanical advantage is unity
(e) none of the above.
Ans: b

136. A cable with a uniformly distributed
load per horizontal meter run will take the following shape
(a) straight line
(b) parabola
(c) hyperbola
(d) elliptical
(e) part of a circle.
Ans: b

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