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question_answer1)
When a light and a heavy body have equal K.E, then which one has a greater momentum?
A)
light body done
clear
B)
heavy body done
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C)
both have equal momentum done
clear
D)
uncertain done
clear
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question_answer2)
In SI system, the unit of P.E. is
A)
erg done
clear
B)
dyne-cm done
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C)
\[J\] done
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D)
none of these done
clear
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question_answer3)
Kilowatt hour (\[\text{kWh}\]) represents the unit of
A)
power done
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B)
impulse done
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C)
momentum done
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D)
none of these done
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question_answer4)
When speed of a motor car increases six times, then kinetic energy increases by
A)
6 times done
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B)
36 times done
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C)
12 times done
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D)
24 times done
clear
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question_answer5)
1 kWh equals
A)
\[\text{36 }\times \text{ 1}{{0}^{\text{2}}}\text{ Joules}\] done
clear
B)
\[\text{36 }\times \text{ 1}{{0}^{\text{4}}}\text{ Joules}\] done
clear
C)
\[\text{3}.\text{6 }\times \text{ 1}{{0}^{\text{6}}}\text{ Joules}\] done
clear
D)
none of these done
clear
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question_answer6)
When speed of the moving object is doubled its
A)
acceleration is doubled done
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B)
momentum becomes four times more done
clear
C)
K. E. is increased to four times done
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D)
potential energy is increased done
clear
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question_answer7)
When time taken to complete a given amount of work increases, then
A)
power increases done
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B)
power decreases done
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C)
energy increases done
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D)
energy decreases done
clear
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question_answer8)
When the force applied and the displacement of the body are inclined at \[30{}^\circ \] with each other, then work done is
A)
infinite done
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B)
maximum done
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C)
zero done
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D)
unity done
clear
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question_answer9)
The K.E. of a body in increased most by doubling its
A)
mass done
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B)
weight done
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C)
speed done
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D)
density done
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question_answer10)
The energy required to raise a given volume of water from a well can be
A)
mega watts done
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B)
mega newton done
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C)
mega joules done
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D)
kilowatts done
clear
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question_answer11)
The slope of kinetic-energy-displacement curve of a particle in motion is
A)
equal to the acceleration of the particle done
clear
B)
inversely proportional to the acceleration done
clear
C)
directly proportional to the acceleration done
clear
D)
none of these done
clear
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question_answer12)
If a force F is applied on a body and it moves with velocity v, then power will be
A)
\[F\times \upsilon \] done
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B)
\[\frac{F}{{{\upsilon }^{2}}}\] done
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C)
\[\frac{F}{\upsilon }\] done
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D)
\[F\times {{v}^{2}}\] done
clear
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question_answer13)
The displacement \[x\] of a particle moving in one dimension, under the action of a constant force, is related to the time t by the equation,\[t=\sqrt{x}+3\]where \[x\] is in metres and t in seconds. The displacement of the particle when its velocity is zero, is
A)
0 done
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B)
6 m done
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C)
12m done
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D)
18m done
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question_answer14)
The relationship between force and position is shown in the figure (in One dimensional case). Work done by the force is displacing a body from \[x\] = 1 cm to \[x\] = 5 cm is
A)
700 ergs done
clear
B)
70 ergs done
clear
C)
60 ergs done
clear
D)
20 ergs done
clear
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question_answer15)
Work done by a centripetal force
A)
increases by decreasing the radius of the circle done
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B)
decreases by increasing the radius of the circle done
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C)
increases by increasing the mass of the body done
clear
D)
is always zero done
clear
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question_answer16)
A 1 kg mass falls from a height of 10 m into a sand box. What is the speed of the mass just before hitting the sand box? If it travels a distance of 2 cm into the sand before coming to rest, what is the average retarding force?
A)
12 m/sec and 3600N done
clear
B)
14 m/sec and 4900N done
clear
C)
16 m/sec and 6400N done
clear
D)
18 m/sec and 8100N done
clear
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question_answer17)
Work done in moving a 50 kg block through a horizontal distance of 10 m by applying a force of 100N which makes an angle of \[60{}^\circ \] with the horizontal is
A)
200 joules done
clear
B)
425 joules done
clear
C)
500 joules done
clear
D)
575 joules done
clear
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question_answer18)
A particle of mass 4 m which is at rest and explodes into three fragments. Two of the fragments each of mass \[m\] are found to move with a speed \[\upsilon \] in mutually perpendicular directions. The total energy released in the explosion is
A)
\[\text{2m}{{\upsilon }^{\text{2}}}\] done
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B)
\[\frac{1}{2}\text{ m}{{\upsilon }^{\text{2}}}\] done
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C)
\[\text{m}{{\upsilon }^{\text{2}}}\] done
clear
D)
\[\frac{3}{2}\text{m}{{\upsilon }^{\text{2}}}\] done
clear
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question_answer19)
\[kWh\] is the unit of
A)
force done
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B)
power done
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C)
time done
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D)
energy done
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question_answer20)
A man throws the bricks to the height of 12 m where they reach with a speed of 12 m/s. If he throws the bricks such that they just reach this height, then what percentage of energy will he save?
A)
19% done
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B)
38% done
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C)
57% done
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D)
76% done
clear
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question_answer21)
The potential energy of a certain spring when stretched through a distance 'S' is 10 joules. The amount of work (in joule) that must be done on this spring to stretch it through an additional distance "S" will be
A)
30 done
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B)
40 done
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C)
10 done
clear
D)
20 done
clear
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question_answer22)
Two bodies with masses \[{{M}_{A}}\] and \[{{M}_{B}}\] are moving with equal kinetic energy. Their linear momenta are numerically in a ratio \[\left| {{P}_{A}} \right|:\left| {{P}_{B}} \right|\], will be
A)
\[{{M}_{B}}:{{M}_{A}}\] done
clear
B)
\[{{M}_{A}}:{{M}_{B}}\] done
clear
C)
\[\sqrt{{{M}_{A}}}:\sqrt{{{M}_{B}}}\] done
clear
D)
\[{{M}_{A}}^{2}:{{M}_{B}}^{2}\] done
clear
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question_answer23)
A ball is allowed to fall from a height of 10 there is 40% loss of energy due to impact, after one impact ball will go upto
A)
10 m done
clear
B)
8 m done
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C)
4m done
clear
D)
6m done
clear
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question_answer24)
Mechanical work done is equal to (symbols have their usual meanings)
A)
\[W=\frac{F}{S}\] done
clear
B)
\[W=FS\] done
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C)
\[W=F+S\] done
clear
D)
\[W=F-S\] done
clear
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question_answer25)
A body at rest can have
A)
speed done
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B)
energy done
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C)
momentum done
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D)
velocity done
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question_answer26)
An elevator is designed to lift a load of 1000 kg, through 6 floors of a building averaging \[\text{3}\text{.5 m}\]per floor in 6 sec. Power of the elevator, neglecting other losses, will be
A)
\[\text{3}\text{.43 }\times \text{ 1}{{0}^{\text{4}}}\text{ watt}\] done
clear
B)
\[\text{4}\text{.33 }\times \text{ 1}{{0}^{\text{4}}}\text{ watt}\] done
clear
C)
\[\text{2}\text{.21 }\times \text{ 1}{{0}^{\text{4}}}\text{ watt}\] done
clear
D)
\[\text{5}\text{.65 }\times \text{ 1}{{0}^{\text{4}}}\text{ watt}\] done
clear
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question_answer27)
A car of mass 2000 kg is to be stopped from a speed of 72 km/hr. If the coefficient of friction between tyres and road is 0.4, then distance travelled before coming to rest is \[\left( \text{g }=\text{ 1}0\text{ m}/{{\text{s}}^{\text{2}}} \right)\]
A)
25 m done
clear
B)
50 m done
clear
C)
75 m done
clear
D)
100 m done
clear
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question_answer28)
Which of the following physical quantity is different from others?
A)
Work done
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B)
Kinetic energy done
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C)
Force done
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D)
Potential energy done
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question_answer29)
When a body is whirled in a circle, then work done on it is
A)
positive done
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B)
negative done
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C)
zero done
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D)
infinite done
clear
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question_answer30)
A tennis ball dropped from a height of 2 m rebounds only 1.5 m after hitting the ground. What fraction of energy is lost in the impact?
A)
\[\frac{1}{4}\] done
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B)
\[\frac{1}{8}\] done
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C)
\[\frac{1}{2}\] done
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D)
\[\frac{1}{16}\] done
clear
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question_answer31)
A crane is used to lift 1000 kg of coal from a mine 100 m deep. If the time taken by the crane is 1 hr then find the power of the crane, assuming the efficiency of the crane to be 80%. \[\left( \text{g }=\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}} \right)\]
A)
2567 watts done
clear
B)
2403 watts done
clear
C)
3403 watts done
clear
D)
3761 watts done
clear
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question_answer32)
A uniform chain of length L and mass M is lying on a smooth table and one-third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, then work required to pull the hanging part on to the table is
A)
\[MgL\] done
clear
B)
\[\frac{MgL}{3}\] done
clear
C)
\[\frac{MgL}{9}\] done
clear
D)
\[\frac{MgL}{18}\] done
clear
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question_answer33)
Unit of power is
A)
watt per second done
clear
B)
joule done
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C)
watt done
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D)
none of these done
clear
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question_answer34)
The mass of an object P is double the mass of object \[Q\]. If both move with the same velocity, then ratio of K.E. of \[P\] to \[Q\] is
A)
1: 2 done
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B)
2 : 1 done
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C)
1 : 4 done
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D)
4 : 1 done
clear
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question_answer35)
1 hp is equal to
A)
0.746 kW done
clear
B)
7.46 kW done
clear
C)
74.6 kW done
clear
D)
746 kW done
clear
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question_answer36)
A truck can move up a road having the grade of 1 m rise for every 50 m with a speed of 15 km/hr. The resisting force is equal to \[\frac{1}{25}\] th the weight Au of the truck. How fast will the same truck move down the hill with the same horse power?
A)
30 km/hr done
clear
B)
45 km/hr done
clear
C)
60km7hr done
clear
D)
75 km/hr done
clear
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question_answer37)
A bullet is fired at a target with a velocity 80 m/s and penetrates 50 cm into it. If this bullet were fired into a target 25 cm thick with equal velocity, with what velocity would it emerge, supposing the resistance to be uniform and the same in both the cases?
A)
\[\sqrt{80}m/s\] done
clear
B)
\[\frac{40}{\sqrt{2}}m/s\] done
clear
C)
\[40m/s\] done
clear
D)
\[40\sqrt{2}m/s\] done
clear
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question_answer38)
A body of mass 1 kg strikes elastically with another body at rest and continues to move in the same direction with one fourth the initial velocity. The mass of the other body is
A)
3 kg done
clear
B)
0.6kg done
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C)
2.4kg done
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D)
4kg done
clear
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question_answer39)
A body rolling down a hill has
A)
K.E. only done
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B)
RE. only done
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C)
neither K.E. nor RE. done
clear
D)
both [a] and [b] done
clear
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question_answer40)
A stretched spring possesses
A)
kinetic energy done
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B)
elastic potential energy done
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C)
electric energy done
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D)
magnetic energy done
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question_answer41)
If L, M denote the angular momentum and mass of a particle and p its linear momentum. Which of the following can represent the kinetic energy of the particle moving in a circle of radius R?
A)
\[\frac{{{L}^{2}}}{2M}\] done
clear
B)
\[\frac{{{P}^{2}}}{M}\] done
clear
C)
\[\frac{{{L}^{2}}}{2M{{R}^{2}}}\] done
clear
D)
\[\frac{1}{2}Mp\] done
clear
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question_answer42)
A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to
A)
\[{{t}^{\frac{3}{2}}}\] done
clear
B)
\[{{t}^{\frac{1}{2}}}\] done
clear
C)
\[{{t}^{\frac{3}{4}}}\] done
clear
D)
\[{{t}^{2}}\] done
clear
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question_answer43)
A machine, which is 75 percent efficient uses 12 joules of energy in lifting up a 1 kg mass through a certain distance. The mass is then allowed to fall through that distance. What will its velocity be at the end of its fall?
A)
\[\sqrt{\text{32}}\text{ m}/\text{s}\] done
clear
B)
\[\sqrt{\text{24}}\text{ m}/\text{s}\] done
clear
C)
\[\sqrt{\text{l8}}\text{ m}/\text{s}\] done
clear
D)
\[\sqrt{\text{9}}\text{ m}/\text{s}\] done
clear
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question_answer44)
When a person climbs a hill, he possesses
A)
only K.E. done
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B)
only RE. done
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C)
both K.E. and RE. done
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D)
none of these done
clear
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question_answer45)
A particle of mass m moves in a circular orbit of radius r under in action of an attractive force \[\frac{-{{K}^{2}}}{{{r}^{2}}}\] which always acts towards the centre r of the orbit. What is the total energy in the particle?
A)
\[\frac{k}{{{r}^{2}}}\] done
clear
B)
\[\frac{2k}{r}\] done
clear
C)
\[\frac{{{k}^{2}}}{r}\] done
clear
D)
\[\frac{k}{2r}\] done
clear
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question_answer46)
Which of the following graphs closely represents the kinetic energy (K) of a freely falling body and its height (h) above the ground?
A)
B)
C)
D)
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question_answer47)
A stone of mass m kg is whirled in a vertical circle of radius 20 cm. The difference in the kinetic energies at the lowest and the topmost positions is
A)
4 mg joules done
clear
B)
0.4 mg joules done
clear
C)
40 mg joules done
clear
D)
None of these done
clear
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question_answer48)
The bag of sand of mass 2 kg is suspended by a rope. A bullet of mass 10 g is fired at it and gets embedded into it. The bag rises up a vertical height of 10 cm. The initial velocity of the bullet is nearly
A)
70 m/s done
clear
B)
140 m/s done
clear
C)
210 m/s done
clear
D)
280 m/s done
clear
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question_answer49)
Which of the following graphs closely represents the P.E (U) of a freely falling body and its height (h) above the ground?
A)
B)
C)
D)
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question_answer50)
A rope ladder with a length 1 carrying a man with a mass m at its end is attached to the basket of balloon with a mass M. The entire system if equilibrium in the air. As the man climbs up the ladder into the balloon, the balloon descend by a height h. Then the potential energy of the man
A)
increases by \[mg\]\[\left( \text{1}-\text{h} \right)\] done
clear
B)
increases b \[mgl\] done
clear
C)
increases by \[mgh\] done
clear
D)
increases by mg \[(2l-h)\] done
clear
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question_answer51)
In question No. 50, the potential energy of the balloon
A)
decreases by \[mgh\] done
clear
B)
increases by \[mgh\] done
clear
C)
increases by \[mg(1-h)\] done
clear
D)
increases by \[mgl\] done
clear
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question_answer52)
In question No. 50, the work down by the man is
A)
\[mgl\] done
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B)
\[mgh\] done
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C)
\[\frac{1}{2}mgl\] done
clear
D)
\[mg(1-h)\] done
clear
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question_answer53)
The heart of a man pumps 4000 c.c. of blood through the arteries/per minute at a pressure of 130 mm Hg. If the density of mercury is\[13.6\times {{10}^{3}}\,kg/{{m}^{3}}\], what is the power of heart?
A)
\[1.15\] watt done
clear
B)
\[2.30\]watt done
clear
C)
\[1.15\] H.P done
clear
D)
\[0.115\] H.P done
clear
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question_answer54)
Once a choice made regarding zero potential energy reference state, the changes in potential energy
A)
are same done
clear
B)
are different done
clear
C)
depend strictly on the choice of the zero potential done
clear
D)
become in determine done
clear
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question_answer55)
Two spheres of the same diameter, one of mass 5 kg and the other of 1 kg are dropped at the same time from the top of a tower. When they are 1 metre above the ground the two sphere have the same
A)
momentum done
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B)
kinetic energy done
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C)
potential energy done
clear
D)
acceleration done
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question_answer56)
It is easier to draw a Wooden block along an inclined plane than to rise it vertically, because
A)
friction decreased done
clear
B)
only part of the weight is to be overcome done
clear
C)
g is decreased done
clear
D)
none of the above done
clear
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question_answer57)
A bag P (mass M) hangs by a long thread and a bullet (mass m) comes horizontally with velocity v and gets caught in the bag. Then for the combined (bag + bullet) system
A)
momentum is \[\frac{m\upsilon M}{M+m}\] done
clear
B)
kinetic energy is \[\frac{m{{V}^{2}}}{2}\] done
clear
C)
momentum is \[\frac{m\upsilon (M+m)}{M}\] done
clear
D)
kinetic energy is \[\frac{{{m}^{2}}{{v}^{2}}}{2(M+m)}\] done
clear
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question_answer58)
The work down in time t on a body of mass m which is accelerated from rest to a speed \[{{v}_{1}}\] in time \[{{t}_{1}}\] as a function of time t is given by
A)
\[\frac{1}{2}m\frac{{{\upsilon }_{1}}}{{{t}_{1}}}{{t}^{2}}\] done
clear
B)
\[m\frac{{{\upsilon }_{1}}}{{{t}_{1}}}{{t}^{2}}\] done
clear
C)
\[\frac{1}{2}{{\left( \frac{m{{\upsilon }_{1}}}{{{t}_{1}}} \right)}^{2}}{{t}^{2}}\] done
clear
D)
\[\frac{1}{2}m{{\frac{{{\upsilon }_{1}}}{{{t}_{1}}}}^{2}}{{t}^{2}}\] done
clear
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question_answer59)
A neutron travelling with a velocity v and kinetic energy E collides perfectly elastically head on with the nucleus of an atom of mass number A at rest. The fraction of total energy retained by the neutron is
A)
\[{{\left( \frac{A-1}{A+1} \right)}^{2}}\] done
clear
B)
\[{{\left( \frac{A+1}{A-1} \right)}^{2}}\] done
clear
C)
\[{{\left( \frac{A-1}{A} \right)}^{2}}\] done
clear
D)
\[{{\left( \frac{A+1}{A} \right)}^{2}}\] done
clear
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question_answer60)
A moving body with a mass \[{{m}_{2}}\]\[{{m}_{1}}\] strike a stationary body of mass \[{{m}_{2}}\]. The masses \[{{m}_{2}}\]and \[{{m}_{2}}\] should be in the ratio \[\frac{{{m}_{1}}}{{{m}_{2}}}\] so as to decrease the velocity of the first body \[1.5\] times assuming a perfectly elastic impact. Then the ratio \[\frac{{{m}_{1}}}{{{m}_{2}}}\] is
A)
\[\frac{1}{25}\] done
clear
B)
\[\frac{1}{5}\] done
clear
C)
5 done
clear
D)
25 done
clear
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question_answer61)
A particle moving along a line travels a distance of 10 m under the action of a force of 5 N. If the work done is 25 J, then the angle between the force and the direction of motion is
A)
\[0{}^\circ \] done
clear
B)
\[30{}^\circ \] done
clear
C)
\[45{}^\circ \] done
clear
D)
\[60{}^\circ \] done
clear
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question_answer62)
A metre rod of mass 1-2 kg is pivoted at one end and hangs vertically. It is displaced through an angle of \[60{}^\circ \]. The increase in potential energy is........ Given : \[g=10\,m{{s}^{-2}}\]
A)
1 Joule done
clear
B)
\[1.5\] Joule done
clear
C)
3 Joule done
clear
D)
6 Joule done
clear
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question_answer63)
A motor of power P is employed to deliver water at a certain rate from a given pipe. In order to obtain thrice as much water from the same pipe in the same time, another motor of power P' is required. Given:\[\text{g}=\text{9}.\text{3489 m}{{\text{s}}^{\text{-2}}}\]Now, the ratio \[P'/P\] equals
A)
27 done
clear
B)
81 done
clear
C)
561 done
clear
D)
\[{{\left( \text{9}.\text{3489} \right)}^{\text{3}}}\] done
clear
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question_answer64)
The angle between the applied force and the momentum at time is
A)
\[0{}^\circ \] done
clear
B)
\[30{}^\circ \] done
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C)
\[60{}^\circ \] done
clear
D)
\[90{}^\circ \] done
clear
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question_answer65)
A 500 gm ball is thrown vertically upwards with a kinetic energy 58.8 J. The kinetic energy is reduced to half at a height of.......... metre above the point of throw,
A)
2m done
clear
B)
3 m done
clear
C)
5m done
clear
D)
6 m done
clear
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question_answer66)
An anti-aircraft shell has been fired and it has a kinetic energy\[x\]. It explodes in the air. Then the sum of kinetic energies of all the particles is
A)
\[x\] done
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B)
more than \[x\] done
clear
C)
less than \[x\] done
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D)
zero done
clear
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question_answer67)
The kinetic energy acquired by a mass m after travelling a fixed distance from rest under the action of constant force is
A)
directly proportional to\[\sqrt{m}\] done
clear
B)
directly proportional to m done
clear
C)
independent of m done
clear
D)
directly proportional to \[\frac{1}{\sqrt{m}}\] done
clear
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question_answer68)
A body of mass M collides against a wall with a velocity V and rebounds with the same speed. Its change of momentum is
A)
zero done
clear
B)
\[MV\] done
clear
C)
\[-2MV\] done
clear
D)
\[-MV\] done
clear
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question_answer69)
The power of a pump motor is 2 kilowatt. The water raised by the pump per minute to a height of 10 m is nearly
A)
500kg done
clear
B)
7000kg done
clear
C)
1200kg done
clear
D)
zero done
clear
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question_answer70)
A chain is held on a frictionless table with one third of its length hanging over the edge. The total length of the chain is 1 and its mass is m. The work required to pull the hanging part back to the table is
A)
\[2mgl\] done
clear
B)
\[\frac{mgl}{5}\] done
clear
C)
\[\frac{mgl}{9}\] done
clear
D)
\[\frac{mgl}{18}\] done
clear
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question_answer71)
The bob of a simple pendulum (mass m and length1) dropped from a horizontal position strikes a block of the same mass elastically placed on a horizontally frictionless table. The K.E. of the block will be
A)
\[2mgl\] done
clear
B)
\[mgl/2\] done
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C)
\[mgl\] done
clear
D)
0 done
clear
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question_answer72)
A mass M is attached to a massless spring of spring constant K. The mass is moved through a distance \[X\] and released. The maximum velocity of the mass is
A)
\[\frac{2\pi M}{K}\] done
clear
B)
\[\frac{K}{Mx}\,\frac{\sqrt{K}}{M}\] done
clear
C)
\[\frac{\sqrt{K}}{M}\] done
clear
D)
\[\frac{\sqrt{K}}{Mx}\] done
clear
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question_answer73)
The kinetic energy of a body is numerically equal to thrice the momentum of the body. The velocity of the body is
A)
2 units done
clear
B)
3 units done
clear
C)
6 units done
clear
D)
9 units done
clear
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question_answer74)
Which of the following is not a perfectly in elastic collision?
A)
Capture of an electron by proton done
clear
B)
Man jumping on to a moving cart done
clear
C)
Collision between glass balls done
clear
D)
A bullet fired into a block of wood such that it is embedded in the wood done
clear
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question_answer75)
A body of mass m moving with velocity v suffers head on elastic collision with another body of mass 2 m at rest. The ratio of the kinetic energy off colliding body before and after collision is
A)
9:1 done
clear
B)
12:1 done
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C)
16 : 1 done
clear
D)
18 : 1 done
clear
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question_answer76)
A body of mass 2 kg is sliding with a constant velocity of 4 m/sec on a frictionless horizontal table. The force required to keep the body movie with the same velocity is
A)
\[8N\] done
clear
B)
\[0\,N\] done
clear
C)
\[2\times {{4}^{2}}N\] done
clear
D)
\[\frac{1}{2}N\] done
clear
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question_answer77)
An open knife edge of mass M is dropped from a height h on a wooden floor. If the blade penetrates S into the wood, the average resistance offered by the wood to the blade is
A)
\[Mg\] done
clear
B)
\[Mg\left( 1+\frac{h}{S} \right)\] done
clear
C)
\[Mg(1+hS)\] done
clear
D)
\[mg{{\left( 1+\frac{h}{S} \right)}^{2}}\] done
clear
E)
None of these done
clear
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question_answer78)
Consider and elevator moving downwards with an acceleration a. The force exerted by a passenger of mass m on the floor of the elevator
A)
\[ma\] done
clear
B)
\[ma-mg\] done
clear
C)
\[mg-ma\] done
clear
D)
\[mg+ma\] done
clear
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question_answer79)
A 60 kg man stands on a spring scale in a list At some instant he finds that the scale reading has changed from 60 kg to 50 kg for a while and then comes back to the original mark , What should he conclude?
A)
The lift was in constant motion upwards done
clear
B)
The lift was in constant motion downwards done
clear
C)
The lift while in motion upwards, suddenly stopped done
clear
D)
The lift while in motion downwards, suddenly stopped done
clear
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question_answer80)
A lift is moving downwards with an acceleration equal to the acceleration due to gravity. A body of mass M kept on the floor of the lift is pulled horizontally. If the coefficient of friction is \[\mu \], then the friction resistance offered by the body is
A)
\[Mg\] done
clear
B)
\[\mu Mg\] done
clear
C)
\[2\mu Mg\] done
clear
D)
zero done
clear
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question_answer81)
In question No. 80, if the lift is moving upwards with a uniform velocity then the frictional resistance offered by the body is
A)
\[Mg\] done
clear
B)
\[\mu Mg\] done
clear
C)
\[2\mu Mg\] done
clear
D)
zero done
clear
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question_answer82)
Three particles A, B and C of equal mass, move with equal speed v along the medians of an equilateral triangle as shown in the figure. They collide at centroid G of the triangle. After collision, A comes to rest and B retracts its path with speed v. What is the speed of C after collision?
A)
Zero done
clear
B)
\[\frac{\upsilon }{2}\] done
clear
C)
\[v\] done
clear
D)
\[2v\] done
clear
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question_answer83)
A body of mass 1 kg rests on a smooth surface. Another body B of mass \[0.2\] kg is placed over A as shown. The coefficient of static between A and B is \[0.15\]. B will begin to slide on A if A is pulled with a force greater than
A)
\[1.764N\] done
clear
B)
\[0.1764N\] done
clear
C)
\[0.3N\] done
clear
D)
it will not slide for any F done
clear
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question_answer84)
A person standing on the floor of an elevator drops a coin. The coin reaches the floor of the elevator in a time \[{{t}_{1}}\] if the elevator is stationary and in tune \[{{t}_{2}}\] if it is moving uniformly, then
A)
\[{{t}_{1}}={{t}_{2}}\] done
clear
B)
\[{{t}_{1}}>{{t}_{2}}\] done
clear
C)
\[{{t}_{1}}<{{t}_{2}}\] done
clear
D)
\[{{t}_{1}}<{{t}_{2}}\] or \[{{t}_{1}}>{{t}_{2}}\] depending on whether the left is going up or down. done
clear
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question_answer85)
In a rocket, fuel burns at the rate of\[1\,Kg\,{{s}^{-1}}\]. This fuel is ejected from the rocket with a velocity of\[60\,Km{{s}^{-1}}\]. This exerts a force, in newton, on the rocket of
A)
\[60\,N\] done
clear
B)
\[600\,N\] done
clear
C)
\[6,000\,N\] done
clear
D)
\[60,000\,N\] done
clear
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question_answer86)
A man has fallen into a ditch of width d and two of his friends are slowly pulling him out using a light rope and two fixed pulleys as shown in the figure. What is the force (assumed equal for both the friends) exerted by each friends on the slope?
A)
\[\frac{mg}{4h}\sqrt{{{d}^{2}}+4{{h}^{2}}}\] done
clear
B)
\[\frac{mg}{4h}\times d\] done
clear
C)
\[\frac{mg}{4h}\times \sqrt{{{d}^{2}}+4{{h}^{2}}}\] done
clear
D)
\[\frac{mgh}{d}\] done
clear
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question_answer87)
The monkey B shown in figure, is holding on to the tail of the monkey A which is climbing up a rope. The masses of the monkeys A and B are 5 kg and 2 kg respectively. If A can tolerate a tension of 30 N in its tail, what force should it apply on the rope in order to carry the monkey B with it? Take \[\text{g }=\text{ 1}0\text{ m}/{{\text{s}}^{\text{2}}}\]
A)
between 50 N and \[80N\] done
clear
B)
between 30 N and \[80N\] done
clear
C)
between 70 N and \[150N\] done
clear
D)
between 60 N and \[90N\] done
clear
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question_answer88)
A ball comes back after an elastic collision with a wall. If initial momentum of the ball is P, the impulse on the wall after the collision is
A)
\[P\] done
clear
B)
\[2P\] done
clear
C)
zero done
clear
D)
\[-2P\] done
clear
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question_answer89)
A bullet of mass 10 gm moving with velocity of 100 m/sec hits a wooden log and penetrates it upto thickness of 5 cm. The resistance force of the log is
A)
\[200N\] done
clear
B)
\[500N\] done
clear
C)
\[1000N\] done
clear
D)
\[600N\] done
clear
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