91. A shell travelling with a horizontal velocity of 100 m/sec explodes and splits into two parts, one of mass 10 kg and the other of 15 kg. The 15 kg mass drops vertically downward with initial velocity of 100 m/sec and the 10 kg mass begins to travel at an angle to the horizontal of tan"1 x, where x is
a) 3/4
b) 4/5
c) 5/3
d) 3/5
Ans: d
92. A car goes round a curve of radius 100 m at 25 m/sec. The angle to the horizontal at which the road must be banked to prevent sideways friction on the car wheels is tan"1 x, where x is (Assume g = 10 m/sec2)
a) 3/8
b) 1/2
c) 9/5
d) 5/8
Ans: d
93. A shell of mass 100 kg travelling with a velocity of 10 m/sec breaks into two equal pieces during an explosion which provides an extra kinetic energy of 20000 Joules. If the pieces continue to move in the same
direction as before, then the speed of the faster one must be
a) 20 m/sec
b) 30 m/sec
c) 40 m/sec
d) 50 m/sec
Ans: b
94. If a flywheel increases its speed from 10 rpm to 20 rpm in 10 seconds, then its angular acceleration is
a) 3.14 rad/sec 10
b) 3.14 rad/sec 20
c) 3.14 rad/sec 30
d) none of the above
Ans: c
95. Two objects moving with uniform speeds are 5 m apart after 1 second when they move towards each other and are 1 m apart when they move in the same direction.
The speeds of the objects are
a) 2 m/sec and 2 m/sec
b) 3 m/sec and 2 m/sec
c) 3 m/sec and 3 m/sec
d) 4 m/sec and 6 m/sec
Ans: b
96. The angular speed of a car taking a circular turn of radius 100 m at 36 km/hr will be
a) 0.1 rad/sec
b) 1 rad/sec
c) 10 rad/sec
d) 100 rad/sec
Ans: a
97. A bullet weighing 10 gm moves with a velocity of lkm/sec. Its kinetic energy is
i) 5000 N.m
ii) 5000 kg.m
iii) 5000 J The correct answer is
a) only (ii)
b) both (i) and (iii)
c) both (ii) and (iii)
d) all (i), (ii) and (iii)
Ans: b
98. A stone was thrown vertically upwards from the ground with a velocity of 50 m/sec. After 5 seconds another stone was thrown vertically upwards from the same place. If both the stones strike the ground at the same time, then the velocity with which the second stone was thrown should be (Assume g = 10 m/sec2)
a) 15 m/sec
b) 25 m/sec
c) 40 m/sec
d) 50 m/sec
Ans: b
99. The condilion for a lifting machine to be reversible is that its efficiency should be
a) less than 50%
b) more than 50%
c) more than 66.67%
d) equal to 100%
Ans: b
100. In a lifting machine a weight of 5 kN is lifted through 200 mm by an effort of 0.1 kN moving through 15 m. The mechanical advantage and velocity ratio of the machine are respectively
a) 50 and 75
b) 75 and 50
c) 75 and 75
d) 50 and 50
Ans: a
a) 3/4
b) 4/5
c) 5/3
d) 3/5
Ans: d
92. A car goes round a curve of radius 100 m at 25 m/sec. The angle to the horizontal at which the road must be banked to prevent sideways friction on the car wheels is tan"1 x, where x is (Assume g = 10 m/sec2)
a) 3/8
b) 1/2
c) 9/5
d) 5/8
Ans: d
93. A shell of mass 100 kg travelling with a velocity of 10 m/sec breaks into two equal pieces during an explosion which provides an extra kinetic energy of 20000 Joules. If the pieces continue to move in the same
direction as before, then the speed of the faster one must be
a) 20 m/sec
b) 30 m/sec
c) 40 m/sec
d) 50 m/sec
Ans: b
94. If a flywheel increases its speed from 10 rpm to 20 rpm in 10 seconds, then its angular acceleration is
a) 3.14 rad/sec 10
b) 3.14 rad/sec 20
c) 3.14 rad/sec 30
d) none of the above
Ans: c
95. Two objects moving with uniform speeds are 5 m apart after 1 second when they move towards each other and are 1 m apart when they move in the same direction.
The speeds of the objects are
a) 2 m/sec and 2 m/sec
b) 3 m/sec and 2 m/sec
c) 3 m/sec and 3 m/sec
d) 4 m/sec and 6 m/sec
Ans: b
96. The angular speed of a car taking a circular turn of radius 100 m at 36 km/hr will be
a) 0.1 rad/sec
b) 1 rad/sec
c) 10 rad/sec
d) 100 rad/sec
Ans: a
97. A bullet weighing 10 gm moves with a velocity of lkm/sec. Its kinetic energy is
i) 5000 N.m
ii) 5000 kg.m
iii) 5000 J The correct answer is
a) only (ii)
b) both (i) and (iii)
c) both (ii) and (iii)
d) all (i), (ii) and (iii)
Ans: b
98. A stone was thrown vertically upwards from the ground with a velocity of 50 m/sec. After 5 seconds another stone was thrown vertically upwards from the same place. If both the stones strike the ground at the same time, then the velocity with which the second stone was thrown should be (Assume g = 10 m/sec2)
a) 15 m/sec
b) 25 m/sec
c) 40 m/sec
d) 50 m/sec
Ans: b
99. The condilion for a lifting machine to be reversible is that its efficiency should be
a) less than 50%
b) more than 50%
c) more than 66.67%
d) equal to 100%
Ans: b
100. In a lifting machine a weight of 5 kN is lifted through 200 mm by an effort of 0.1 kN moving through 15 m. The mechanical advantage and velocity ratio of the machine are respectively
a) 50 and 75
b) 75 and 50
c) 75 and 75
d) 50 and 50
Ans: a
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