# 240+ Engineering Mechanics Solved MCQs

48
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1.

A. TRUE
B. False
2.

A. halved
B. doubled
3.

A. N - m
B. m / s
C. m / s2
4.

## The loss of kinetic energy due to direct impact of two bodies

A. depends
B. does not depend
5.

## If a given force (or a given system of forces) acting on a body

A. change
B. does not change
6.

## For any system of coplaner forces, the condition of equilibrium is that the

A. algebraic sum of the horizontal components of all the forces should be zero
B. algebraic sum of the vertical components of all the forces should be zero
C. algebraic sum of moments of all the forces about any point should be zero
D. all of the above
Answer» D. all of the above
7.

A. 50
B. 100
C. 150
D. 200
8.

A. equal to
B. less than
C. greater than
9.

## The angle of inclination of the plane at which the body begins to move down the plane, is called

A. angle of friction
B. angle of repose
C. angle of projection
D. none of these
10.

A. W sin ?
B. W cos ?
C. W tan ?
D. none of these
11.

A. less than
B. more than
C. equal to
12.

## The forces, whose lines of action are parallel to each other and act in the same directions, are known as

A. coplaner concurrent forces
B. coplaner non-concurrent forces
C. like parallel forces
D. unlike parallel forces
13.

A. Correct
B. Incorrect
14.

A. g / 2
B. g / 3
C. g / 4
D. none of these
15.

A. elastic
B. inelastic
16.

A. True
B. False
17.

## The total energy possessed by a system of moving bodies

A. is constant at every instant
B. varies from point to point
C. is maximum in the start and minimum at the end
D. is minimum in the start and maximum at the end
Answer» A. is constant at every instant
18.

A. ?d3 / 16
B. ?d3 / 32
C. ?d4 / 32
D. ?d4 / 64
19.

## A couple produces

A. translatory motion
B. rotational motion
C. combined translatory and rotational motion
D. none of the above
20.

A. Agree
B. Disagree
21.

A. equal to
B. less than
C. greater than
22.

## Which of the following statement is wrong?

A. A force acting in the opposite direction to the motion of the body is called force of friction.
B. The ratio of the limiting friction to the normal reaction is called coefficient of friction.
C. A machine whose efficiency is 100% is known as an ideal machine.
D. The velocity ratio of a machine is the ratio of load lifted to the effort applied.
Answer» D. The velocity ratio of a machine is the ratio of load lifted to the effort applied.
23.

## When a rigid body is suspended vertically, and it oscillates with a small amplitude under the action of the force of gravity, the body is known as

A. simple pendulum
B. compound pendulum
C. torsional pendulum
D. second's pendulum
24.

A. stable
B. unstable
C. neutral
25.

## A machine having an efficiency less than 50%, is known as

A. reversible machine
B. non-reversible machine
C. neither reversible nor non-reversible machine
D. ideal machine
26.

## A framed structure is perfect, if the number of members are

A. equal to
B. less than
C. greater than
D. either (b) or (c)
27.

## A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act

A. downward at its upper end
B. upward at its upper end
C. zero at its upper end
D. perpendicular to the wall at its upper end
Answer» C. zero at its upper end
28.

A. True
B. False
29.

A. equal to
B. less than
C. greater than
30.

## One watt is equal to

A. 0.1 joule / s
B. 1 joule / s
C. 10 joules / s
D. 100 joules / s
Answer» B. 1 joule / s
31.

A. Correct
B. Incorrect
32.

A. ?.y
B. ?2.y
C. ?2/y
D. ?3.y
33.

## The power developed by a body acted upon by a torque T newton metre (N - m) and revolving at ? radian / s is given by

A. T.? (in watts)
B. T.? / 60 (in watts)
C. T.? / 75 (in kilowatts)
D. T.? / 4500 (in kilowatts)
34.

A. Right
B. Wrong
35.

## The friction experienced by a body, when at rest, is known as

A. static friction
B. dynamic friction
C. limiting friction
D. coefficient of friction
36.

A. h / kG
B. h2 / kG
C. k2G / h
D. h x kG
37.

## A smooth cylinder lying on a

A. curved surface
B. convex surface
C. horizontal surface
38.

A. kg-m2
B. kg-m-s2
C. kg/m2
D. m4
39.

A. Yes
B. No
40.

A. 20N
B. 100N
C. 500N
D. none of these
41.

A. True
B. False
42.

A. D + d
B. D - d
C. D x d
D. D / d
43.

A. True
B. False
44.

A. Agree
B. Disagree
45.

A. True
B. False
46.

A. True
B. False
47.

A. 30?
B. 60?
C. 90?
D. 120?
48.

## The motion of a particle round a fixed axis is

A. translatory
B. rotary
C. circular
D. translatory as well as rotatry
49.

## According to Newton's first law of motion,

A. every body continues in its state of rest or of uniform motion, in a straight line, unless it is acted upon by some external force
B. the rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction, in which the force acts
C. to every action, there is always an equal and opposite reaction
D. none of the above
Answer» A. every body continues in its state of rest or of uniform motion, in a straight line, unless it is acted upon by some external force
50.

A. Correct
B. Incorrect
51.

## Non-coplaner non-concurrent forces are those forces which

A. meet at one point, but their lines of action do not lie on the same plane
B. do not meet at one point and their lines of action do not lie on the same plane
C. do not meet at one point, but their lines of action lie on the same plane
D. none of the above
Answer» B. do not meet at one point and their lines of action do not lie on the same plane
52.

## A machine having an efficiency greater than 50%, is known as

A. reversible machine
B. non-reversible machine
C. neither reversible nor non-reversible machine
D. ideal machine
53.

A. Agree
B. Disagree
54.

A. h / 2
B. h / 3
C. h / 4
D. h / 6
55.

## In order to determine the effects of a force, acting on a body, we must know

A. magnitude of the force
B. line of action of the force
C. nature of the force i.e. whether the force is push or pull
D. all of the above
Answer» D. all of the above
56.

## The ratio of static friction to dynamic friction is always

A. equal to one
B. less than one
C. greater than one
D. none of these
57.

A. Right
B. Wrong
58.

A. 30?
B. 45?
C. 60?
D. 90?
59.

## The mechanical advantage of a lifting machine is the ratio of

A. distance moved by effort to the distance moved by load
B. load lifted to the effort applied
C. output to the input
D. all of the above
60.

A. ?d3 / 16
B. ?d3 / 32
C. ?d4 / 32
D. ?d4 / 64
61.

## The total motion possessed by a body, is called

A. impulsive force
B. mass
C. weight
D. momentum
62.

## Which of the following are vector quantities?

A. Linear displacement
B. Linear velocity
C. Linear acceleration
D. all of these
63.

A. Correct
B. Incorrect
64.

## A weight of 1000 N can be lifted by an effort of 80 N. If the velocity ratio is 20, the machine is

A. reversible
B. non-reversible
C. ideal
65.

A. Right
B. Wrong
66.

## The velocity ratio of a single purchase crab winch can be increased by

A. increasing the length of the handle
C. increasing the number of teeth of the pinion
D. all of the above
Answer» A. increasing the length of the handle
67.

## When two elastic bodies collide with each other,

A. the two bodies will momentarily come to rest after collision
B. the two bodies tend to compress and deform at the surface of contact
C. the two bodies begin to regain their original shape
D. all of the above
Answer» D. all of the above
68.

## Moment of inertia is the

A. second moment of force
B. second moment of area
C. second moment of mass
D. all of these
69.

A. Agree
B. Disagree
70.

A. inward
B. outward
71.

## The bodies which rebound after impact are called

A. inelastic bodies
B. elastic bodies
C. neither elastic nor inelastic bodies
D. none of these
72.

A. first
B. second
C. third
73.

## The energy possessed by a body, for doing work by virtue of its position, is called

A. potential energy
B. kinetic energy
C. electrical energy
D. chemical energy
74.

## The matter contained in a body, is called

A. impulsive force
B. mass
C. weight
D. momentum
75.

## The motion of a wheel of a car is

A. purely translation
B. purely rotational
C. combined translation and rotational
D. none of these
Answer» C. combined translation and rotational
76.

A. P = Q
B. Q = R
C. Q = 2R
D. none of these
77.

A. bh3 / 4
B. bh3 / 8
C. bh3 / 12
D. bh3 / 36
78.

## According to lami's theorem

A. the three forces must be equal
B. the three forces must be at 120? to each other
C. the three forces must be in equilibrium
D. if the three forces acting at a point are in equilibrium, then each force is proportional to the sine of the angle between the other two
Answer» D. if the three forces acting at a point are in equilibrium, then each force is proportional to the sine of the angle between the other two
79.

A. Agree
B. Disagree
80.

## A pendulum which executes one beat per second is known as

A. simple pendulum
B. compound pendulum
C. torsional pendulum
D. second's pendulum
81.

## 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 known as

A. principle of independence of forces
B. principle of resolution of forces
C. principle of transmissibility of forces
D. none of these
Answer» B. principle of resolution of forces
82.

## Which of the fololowing statement is correct in connection with projectiles?

A. A path, traced by a projectile in the space, is known as trajectory.
B. The velocity with which a projectile is projected, is known as the velocity of projection.
C. The angle, with the horizontal, at which a projectile is projected is known as angle of projection.
D. all of the above
Answer» D. all of the above
83.

A. more
B. less
84.

A. ?3 a/2
B. 2?3 a
C. a/2 ?3
D. 3?2 a
85.

## In a screw jack, the effort required to lift the load is given by. Where W = Load lifted, ? = Helix angle, and ? = Angle of friction

A. P = W tan (? ? ?)
B. P = W tan (? + ?)
C. P = W tan (? - ?)
D. P = W tan (? + ?)
Answer» B. P = W tan (? + ?)
86.

A. equal to
B. less than
C. greater than
87.

A. Agree
B. Disagree
88.

## One joule means that

A. work is done by a force of 1 N when it displaces a body through 1 m
B. work is done by a force of 1 kg when it displaces a body through 1 m
C. work is done by a force of 1 dyne when it displaces a body through 1 cm
D. work is done by a force of 1 g when it displaces a body through 1 cm
Answer» A. work is done by a force of 1 N when it displaces a body through 1 m
89.

A. n
B. n2
C. 2n
D. 2n - 1
90.

A. 1 m
B. 2 m
C. 3 m
D. 4 m
91.

## Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to

A. area of the triangle
B. twice the area of the triangle
C. half the area of the triangle
D. none of these
Answer» B. twice the area of the triangle
92.

A. bh3 / 4
B. bh3 / 8
C. bh3 / 12
D. bh3 / 36
93.

A. TRUE
B. FALSE
94.

## The friction experienced by a body, when in motion, is known as

A. rolling friction
B. dynamic friction
C. limiting friction
D. static friction
95.

A. Agree
B. Disagree
96.

A. perfect
B. imperfect
C. deficient
97.

A. composition
B. resolution
98.

## A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following

A. both the balls undergo an equal change in momentum
B. the change in momentum suffered by rubber ball is more than the lead balf
C. the change in momentum suffered by rubber ball is less than the lead ball
D. none of the above
Answer» B. the change in momentum suffered by rubber ball is more than the lead balf
99.

A. 3r/8
B. 4r/3?
C. 8r / 3
D. 3r / 4?
100.

A. 4
B. 8
C. 16
D. 20