108. According to parallel axis theorem, the moment of
inertia of a section about an axis parallel to the axis
through centre of gravity (i.e. IP) is given by
(a) 2 P G I I Ah
(b) 2P G I I Ah –
(c) 2P G I I Ah /
(d)2PGAh II
where A = Area of the section,I
G = Moment of inertia of the section about an axis passing through its C.G., and
h = Distance between C.G. and the parallel axis.
109. The moment of inertia of a thin disc of mass m and
radius r, about an axis through its centre of gravity
and perpendicular to the plane of the disc is
(a) mr 2 / 2 (b) mr 2 / 4 c) mr 2 / 6 (d) mr 2 / 8
110. The moment of inertia of a thin rod of mass m and
length l, about an axis through its centre of gravity
and perpendicular to its length is
(a) ml2 / 4 (b) ml2 / 6
(c) ml2 / 8 (d) ml2 / 12
111. The moment of inertia of a solid cylinder of mass m,
radius r and length l about the longitudinal axis or
polar axis is
(a) mr
2 / 2 (b) mr
2 / 4
(c) mr
2 / 6 (d) mr
2 / 8
112. The moment of inertia of a thin spherical shell of
mass m and radius r, about its diameter is
(a) mr
2 / 3 (b) 2mr
2 / 3
(c) 2mr
2 / 5 (d) 3mr
2 / 5
113. The moment of inertia of a sphere of mass m and
radius r, about an axis tangential to it, is
(a) 2mr
2 / 3 (b) 2mr
2 / 5
(c) 7mr
2 / 3 (d) 7mr
2 / 5
114. The moment of inertia of a solid sphere of mass m
and radius r is
(a) 2mr
2 / 3 (b) 2mr
2 / 5
(c) mr
2
(d) mr
2 / 2
115. The moment of inertia of a solid cone of mass m and
base radius r about its vertical axis is
(a) 3mr
2 / 5 (b) 3mr
2 / 10
(c) 2mr
2 / 5 (d) 4mr
2 / 5
116. The moment of inertia about centroidal axis parallel
to a side for a cube of mass m is
(a)
2
3
ma
(b)
2
6
ma
(c)
2
8
ma
(d)
2
12
ma
117. The radius of gyration of a solid square disc of side
length a is given by
(a) 2 3
a
(b) 2
a
(c) 3 2
a
(d) 2a
118. A force acting in the opposite direction to the motion
of the body is called force of friction.
(a) Agree (b) Disagree
119. The maximum frictional force, which comes into play,
when a body just begins to slide over the surface of
the other body, is known as
(a) static friction (b) dynamic friction
(c) limiting friction (d) coefficient of friction
120. 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
121. 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
122. The friction experienced by a body, when in motion,
is known as
(a) rolling friction (b) dynamic friction
(c) limiting friction (d) static friction
123. The static friction
(a) bears a constant ratio to the normal reaction
between the two surfaces
(b) is independent of the area of contact, between
the two surfaces
(c) always acts in a direction, opposite to that in
which the body tends to move
(d) all of the above
124. Static friction is always.............dynamic friction.
(a) equal to (b) greater than
(c) less than
125. The angle of the inclined plane at which a body just
begins to slide down the plane, is called helix angle.
(a) True (b) False
126. The angle which the normal reaction makes with the
resultant reaction is called angle of friction.
(a) Agree (b) Disagree
127. 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
128. The minimum force required to slide a body of weight
W on a rough horizontal plane is
(a) W sin T (b) W cosT
(c) W tan T (d) none of these
129. A body will begin to move down an inclined plane if
the angle of inclination of the plane is.........the angle
of friction.
(a) equal to (b) less than
(c) greater than
130. The friction that exists between two unlubricated
surfaces is known as
(a) dry friction (b) unlubricated friction
(c) static friction (d) non-viscous friction
131. The coefficient of friction (P) in terns of angle of
friction (I) is given by
(a) I = tan P (b) P = sin I
(c) P = tan I (d)
1
tan P I
132. Vertex angle of the cone of static friction is
(a) twice the angle of static friction
(b) half the angle of static friction
(c) equal to the angle of static friction
(d) none of the above
133. A body of weight W is required to move up on rough
inclined plane whose angle of inclination with the
horizontal is D. The effort applied parallel to the
plane is given by
(a) P = W tan D
(b) P = W tan (D + I)
(c) P = W (sin D + Pcos D)
(d) P = W (cos D + P sin D)
whereP = tanI = Coefficient of friction between the
plane and the body.
134. Coefficient of friction is the ratio of the limiting
friction to the normal reaction between the two
bodies.
(a) Yes (b) No
135. Coefficient of friction depends upon
(a) area of contact only (b) nature of surface only
(c) both (a) and (b) (d) none of these
136. The force required to move the body up the plane will
be minimum if it makes an angle with the inclined
plane............... the angle of friction.
(a) equal to (b) less than
(c) greater than
137. A ladder is resting on a smooth ground and leaning
against a rough vertical wall. The force of friction
will act
(a) towards the wall at its upper and
(b) away from the wall at its upper end
(c) downward at its upper end
(d) upward at its upper end
138. 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
139. If a ladder is not in equilibrium against a smooth
vertical wall, then it can be made in equilibrium by
(a) decreasing the length of the ladder
(b) increasing the length of the ladder
(c) increasing the angle of inclination
(d) decreasing the angle of inclination
140. In a screw jack, the effort required to lift the load is
given by
(a) P = W tan (D–I) (b) P = W tan (DI)
(c) P = W tan (I–D) (d) P = W cos (DI)
where W = Load lifted, D = Helix angle, and
I = Angle of friction.
141. In a screw jack, the effort required to lower the load
is ............ the effort required to raise the same load.
(a) less than (b) equal to
(c) more than
142. Efficiency of a screw jack is given by
(a) tan ( + )
tan
D I
D
(b)
tan
tan ( )
D
DI
(c) tan ( – )
tan
D I
D
(d)
tan
tan ( – )
D
D I
where D = Helix angle, and I= Angle of friction.
143. The efficiency of a screw jack is maximum, when
(a) D I 45o / 2 (b) D I 45o – / 2
(c) D qI 90 (d) D q I 90 –
where D = Helix angle, and I= Angle of friction.
144. The maximum efficiency of a screw jack is
(a)
1– sin
1 sin
I
I (b)
1 sin
1– sin
I
I
(c)
1– tan
1 tan
I
I (d)
1 tan
1– tan
I
I
145. The velocity ratio in case of an inclined plane inclined
at angle T to the horizontal and weight being pulled
up the inclined plane by vertical effort is
(a) sin T (b) cos T
(c) tan T (d) cosec T
146. An ideal machine is one whose efficiency is
(a) between 60 and 70 %
(b) between 70 and 80%
(c) between 80 and 90 %
(d) 100 %
147. 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
148. The efficiency of a lifting machine is the ratio of
(a) output to the input
(b) work done by the machine to the work done on
the machine
(c) mechanical advantage to the velocity ratio
(d) all of the above
149. If the efficiency of a lifting machine is kept constant,
its velocity ratio is.............proportional to its
mechanical advantage.
(a) directly (b) inversely
150. In ideal machines, mechanical advantage is.............
velocity ratio.
(a) equal to (b) less than
(c) greater than
151. In actual machines, mechanical advantage is............
velocity ratio.
(a) equal to (b) less than
(c) greater than
152. A lifting machine lifts a load of 1000N through a
distance of 0.2 m by means of an effort of 200N
through a distance of 1m. This machine is an ideal
one.
(a) Right (b) Wrong
153. 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
154. 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
155. A machine which is capable of doing work in the
reversed direction, after the effort is removed, is
called a non-reversible machine.
(a) Yes (b) No
156. A machine which is not capable of doing any work
in the reversed direction, after the effort is removed,
is called a reversible machine.
(a) True (b) False
157. A non-reversible machine is also called a self-locking
machine.
(a) Agree (b) Disagree
158. A screw jack used for lifting the loads is
(a) a reversible machine
(b) a non-reversible machine
(c) an ideal machine
(d) none of the above
159. 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
160. For a self locking machine, the efficiency must be
(a) equal to 50% (b) less than 50%
(c) greater than 50% (d) 100%
161. The law of the machine is
(a) P = mW – C (b) P = m / W + C
(c) P = mW + C (d) P = C – mW
where P = Effort applied to lift the load,
m = A constant which is equal to the slope
of the line,
W = Load lifted, and
C = Another constant which represents the
machine friction.
162. The maximum mechanical advantage of a lifting
machine is
(a) 1 + m (b) 1 – m
(c) 1 / m (d) m
163. The maximum efficiency of a lifting machine is
(a) 1 / m (b) V.R. / m
(c) m / V.R. (d) 1 / m × V.R.
164. The velocity ratio for the first system of pulleys is
(a) n (b) n
2
(c) 2n (d) 2n
– 1
where n is the number of pulleys.
165. The velocity ratio for the second system of pulleys
is n.
(a) True (b) False
166. The velocity ratio for the third system of pulleys is
(a) n (b) n
2
(c) 2n
(d) 2n
– 1
167. The velocity ratio of a differential pulley block with
D and d as the diameters of larger and smaller pulley,
is
(a) –
D
D d (b)
D
D d
(c)
2
–
D
D d (d)
2D
D d
168. 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.
169. The velocity ratio of a first system of pulleys with 4
pulleys is
(a) 4 (b) 8
(c) 16 (d) 20
170. Match the correct answer from Group B for the
statements given in Group A.
Group A Group B
(a) M.I. of a circular section about its
diameter (d) (A)
1– sin
1 sin
I
I
(b) Efficiency of a screw jack (B) 1/m
(c) Maximum efficiency of a screw
jack (C) 4
64
d S
u
(d) Maximum mechanical advantage
of a lifting machine (D)
1
mu V.R.
(e) Maximum efficiency of a lifting
machine (E)
tan
tan ( )
D
DI
171. If the number of pulleys in a system is equal to its
velocity ratio, then it is a.............system of pulleys.
(a) first (b) second
(c) third
172. The velocity ratio of a simple wheel and axle with D
and d as the diameters of effort wheel and load axle,
is
(a) D + d (b) D – d
(c) D × d (d) D / d
173. The velocity ratio of a differential wheel and axle with
D as the diameter of effort wheel and d1and d2 as the
diameters of larger and smaller axles respectively, is
(a)
1 2
D
d d (b)
1 2 –
D
d d
(c)
1 2
2D
d d (d)
1 2
174. The velocity ratio of a single purchase winch crab
can be increased by
(a) increasing the length of the handle
(b) increasing the radius of the load drum
(c) increasing the number of teeth of the pinion
(d) all of the above
175. A differential pulley block has larger and smaller
diameters of 100 mm and 80 mm respectively. Its
velocity ratio is
(a) 5 (b) 10
(c) 20 (d) 40
176. In a single threaded worm and worm wheel, the number
of teeth on the worm is 50. The diameter of the effort
wheel is 100 mm and that of load drum is 50 mm. The
velocity ratio is
(a) 50 (b) 100
(c) 150 (d) 200
177. In a wormed geared pulley block, if the number of
teeth on the worm wheel is doubled, then its velocity
ratio is also doubled.
(a) True (b) False
178. The velocity ratio of a simple screw jack with p as the
pitch of the screw and l as the length of effort arm, is
(a)
2 l
p
S (b)
l
p
S
(c)
2 p
l
S (d)
2 p
l
S
179. All the steel trusses of the bridges, have one of their
end roller supported, and other end hinged. The main
advantage of such a support is that the truss remains
stable.
(a) True (b) False
180. A framed structure is perfect, if the number of
members are..............(2j – 3), where j is the number
of joints.
(a) equal to (b) less than
(c) greater than (d) either (b) or (c)
181. A framed structure is imperfect, if the number of
members are.................(2j – 3).
(a) equal to (b) less than
(c) greater than (d) either (b) or (c)
182. A redundant frame is also called..................frame.
(a) perfect (b) imperfect
(c) deficient
183. A framed structure as shown in Fig. 1.49, is a
(a) perfect frame
(b) deficient frame
(c) redundant frame
(d) none of the above
184. In a framed structure, as shown in Fig. 1.50, the force
in the member BC is
(a) W / 3 (compression)
(b) W / 3 (tension)
(c) 2W / 3 (compression)
(d) 2W / 3 (tension)
185. In a framed structure, as shown
in Fig. 1.50, the force in the
member AC is numerically
equal to the force in member
BC.
(a) Right (b) Wrong
186. In a framed structure, as shown in Fig. 1.50, the force
in the member AB is .........the force in member AC.
(a) half (b) equal to
(c) double
187. In a framed structure, as shown in Fig. 1.50, the force
in the member CD is tensile in nature.
(a) Agree (b) Disagree
188. In a framed structure, as shown
in Fig. 1.51, the forces in
the members AB and BC are
respectively.
(a) 3W (tensile) and 2W (compressive)
(b) 2W (tensile) and 3W (compressive)
(c) 2 3W (tensile) and 2 3W (compressive)
(d) none of the above
189. Which of the following is a scalar quantity?
(a) Force (b) Speed
(c) Velocity (d) Acceleration
190. The rate of change of displacement of a body is called
(a) velocity (b) acceleration
(c) momentum (d) none of these
191. Which of the following are vector quantities?
(a) Linear displacement
(b) Linear velocity
(c) Linear acceleration
(d) all of the above
192. The negative acceleration is called retardation.
(a) True (b) False
193. If the body falls freely under gravity, then the
gravitational acceleration is taken as
(a) + 8.9 m/s2
(b) – 8.9 m/s2
(c) + 9.8 m/s2
(d) – 9.8 m/s2
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