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question_answer1)
The action and reaction forces referred to in Newton's third law of motion
A)
Must act on same body done
clear
B)
Must act on different bodies need not be equal in magnitude but must have done
clear
C)
The same line of action done
clear
D)
Must be equal in magnitude but need not have the same line of action done
clear
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question_answer2)
A long-jumper runs before jumping to
A)
Cover greater distance done
clear
B)
Maintain momentum conservation done
clear
C)
Gain energy by running done
clear
D)
Gain momentum done
clear
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question_answer3)
If a rock is brought from the surface of the moon, then
A)
Its mass will change done
clear
B)
Its weight will change, but not mass done
clear
C)
Both mass and weight will change done
clear
D)
Its mass and weight will remain the same done
clear
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question_answer4)
A false balance has equal arms. An object weights \[{{w}_{1}}\] when placed in one pan and \[{{w}_{2}}\] when placed in the other pan. Then weight w of the object is
A)
\[\sqrt{{{w}_{1}}{{w}_{2}}}\] done
clear
B)
\[\frac{{{w}_{1}}+{{w}_{2}}}{2}\] done
clear
C)
\[\left( \frac{{{w}_{1}}^{2}+{{w}_{2}}^{2}}{2} \right)\] done
clear
D)
\[\sqrt{{{w}_{1}}^{2}+{{w}^{2}}_{2}}\] done
clear
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question_answer5)
The force acting on a mass of 1 g due to the gravitational pull on the earth is called 1 g wt. One g wt equals
A)
1 N done
clear
B)
9.8 N done
clear
C)
980 dyne done
clear
D)
None of these done
clear
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question_answer6)
Weight of a body would not be zero
A)
At the centre of the earth done
clear
B)
During a free fall done
clear
C)
In interplanetary space done
clear
D)
On a frictionless surface done
clear
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question_answer7)
Which of the following physical quantities has no unit?
A)
Relative density done
clear
B)
Density done
clear
C)
Pressure done
clear
D)
Thrust done
clear
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question_answer8)
A particle of mass moving eastward with a speed v collides with another particle of the same mass moving northwards with the same speed u. The two particles coalesce on collision. The new particle of mass 2 m will move in the northeasterly direction with a velocity
A)
\[\frac{\sqrt{\upsilon }}{\sqrt{2}}\] done
clear
B)
\[\frac{\upsilon }{2}\] done
clear
C)
\[\frac{\upsilon }{\sqrt{2}}\] done
clear
D)
None of these done
clear
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question_answer9)
Two bodies of masses 0.03 kg, and 0.04 kg, are tied to the ends of a massless string. This string passes over the frictionless pulley. The tension in the string is
A)
0.336 N done
clear
B)
0.294 N done
clear
C)
683N done
clear
D)
0.392 N done
clear
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question_answer10)
In the above problem, acceleration of the system is
A)
\[\text{4}.\text{9 m}/{{\text{s}}^{\text{2}}}\] done
clear
B)
\[\text{2}.\text{94 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
\[\text{1}.\text{4 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
\[\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}}\] done
clear
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question_answer11)
An iron ball and a wooden ball of the same radius are released from a height H in vacuum. The times taken by both of them of reach the ground are
A)
Roughly equal done
clear
B)
Unequal done
clear
C)
Exactly equal done
clear
D)
In the inverse ratio of their diameters done
clear
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question_answer12)
A man is standing on a boat in still water If he walks towards the shore the boat will
A)
Move away from the shore done
clear
B)
Remain stationary done
clear
C)
Move towards the shore done
clear
D)
Sink done
clear
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question_answer13)
During a planned man oeuvre in a space flight, a free-floating astronaut A pushes another Free floating astronaut B, the mass of A being greater than that of B. Then, the magnitude of the force exerted by astronaut A on astronaut B is
A)
Equal to zero done
clear
B)
Equal to the force exerted by B on A done
clear
C)
Greater than the force exerted by B on A done
clear
D)
Less than the force exerted by B on A done
clear
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question_answer14)
In the above problem, during a push
A)
Acceleration of A is greater than that of B done
clear
B)
Acceleration of A is less than that of B done
clear
C)
Neither is accelerated done
clear
D)
Their accelerations are equal in magnitude but opposite in direction done
clear
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question_answer15)
A body of mass 300 gm is at rest. What force in Newton will you have to apply to move it through 200 cm in 10 sec.?
A)
Zero done
clear
B)
12 Newton done
clear
C)
1.2 Newton done
clear
D)
0.12 Newton done
clear
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question_answer16)
A body of mass 2 kg is acted upon by two forces each of magnitude 1 Newton, making an angle of \[60{}^\circ \] with each other. The net acceleration of the body (in\[\text{m}/{{\text{s}}^{\text{2}}}\]) is
A)
\[\frac{\sqrt{2}}{3}\] done
clear
B)
\[\frac{\sqrt{3}}{2}\] done
clear
C)
0.5 done
clear
D)
1.0 done
clear
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question_answer17)
A parachutist of weight w strikes the ground and comes to rest with an upward acceleration of magnitude 3 g. Force exerted on him by the ground during landing is
A)
\[2w\] done
clear
B)
3 \[w\] done
clear
C)
4 \[w\] done
clear
D)
5 \[w\] done
clear
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question_answer18)
A boat of mass 3000 kg, initially at rest is pulled by a force of \[\text{1}.\text{8 x 1}{{0}^{\text{4}}}\] Newton through a distance of 3 m. Assuming that the resistance due to water is negligible, velocity of boat is
A)
6 m/s done
clear
B)
8 m/s done
clear
C)
9 m/s done
clear
D)
11 m/s done
clear
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question_answer19)
A bullet of mass A and velocity B is fired into a block of wood of mass C. If loss of any mass and friction be neglected, then velocity of the system must be
A)
\[\frac{AB}{A+C}\] done
clear
B)
\[\frac{A+C}{B+C}\] done
clear
C)
\[\frac{AC}{B+C}\] done
clear
D)
\[\frac{A+B}{AC}\] done
clear
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question_answer20)
A dish of mass 10 gm is kept horizontally in air by firing bullets of mass 5 g each at the rate of 10 per sec. If the bullets rebound with the same speed, what is the velocity with which the bullets are fired?
A)
49 cm/sec done
clear
B)
147 cm/sec done
clear
C)
98 cm/sec done
clear
D)
196 cm/sec done
clear
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question_answer21)
Three equal weights of mass 2 kg each are hanging on a string passing over a fixed pulley as shown in the fig. What is the tension in the string connecting the weights B and C?
A)
Zero done
clear
B)
13 N done
clear
C)
3.3 M done
clear
D)
19.6 N done
clear
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question_answer22)
In the arrangement shown in figure below, the ends P and Q of an stretchable string move downwards with uniform speed u. Pulleys A and B are fixed. Mass M moves upwards with a speed
A)
\[2u\cos \theta \] done
clear
B)
\[u\cos \theta \] done
clear
C)
\[\frac{2u}{\cos \theta }\] done
clear
D)
\[\frac{u}{\cos \theta }\] done
clear
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question_answer23)
A body of mass 1 kg initially at rest, explodes and breaks into three fragments of masses in the ratio 1:1:3. The two pieces of equal masses fly off perpendicular to each other with a speed of 30 m/s each. What is the velocity of the heavier fragment?
A)
10 m/s done
clear
B)
20 m/s done
clear
C)
\[10\sqrt{2}\,\,m/s\] done
clear
D)
\[20\sqrt{2}\,\,m/s\] done
clear
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question_answer24)
Two bodies with masses \[{{m}_{1}}\] and \[{{m}_{2}}\] \[({{m}_{1}}>{{m}_{2}})\] are joined by a string passing over a fixed pulley. The centres of gravity of the two bodies are initially at the same height. Assume mass of the pulley and weight of the thread negligible. Then the downwards acceleration of \[{{m}_{1}}\] is
A)
\[\left( \frac{{{m}_{1}}-{{m}_{2}}}{{{m}_{1}}+{{m}_{2}}} \right)g\] done
clear
B)
\[{{\left( \frac{{{m}_{1}}-{{m}_{2}}}{{{m}_{1}}+{{m}_{2}}} \right)}^{2}}g\] done
clear
C)
\[\frac{{{m}_{2}}g}{{{m}_{1}}+{{m}_{2}}}\] done
clear
D)
\[\frac{{{m}_{1}}g}{{{m}_{1}}+{{m}_{2}}}\] done
clear
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question_answer25)
In the above question, the time after which the centres of gravity of the two bodies will have a separation h, is
A)
\[\sqrt{\frac{h}{g}{{\left( \frac{{{m}_{2}}+{{m}_{2}}}{{{m}_{2}}-{{m}_{2}}} \right)}^{2}}}\] done
clear
B)
\[\sqrt{\frac{h}{g}\left( \frac{{{m}_{1}}+{{m}_{2}}}{{{m}_{1}}-{{m}_{2}}} \right)}\] done
clear
C)
\[\sqrt{\frac{2h}{g}\left( \frac{{{m}_{2}}+{{m}_{2}}}{{{m}_{2}}-{{m}_{2}}} \right)}\] done
clear
D)
\[\sqrt{\frac{h}{2g}\left( \frac{{{m}_{2}}+{{m}_{2}}}{{{m}_{2}}-{{m}_{2}}} \right)}\] done
clear
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question_answer26)
A number of discs, each of momentum M kg m/s are striking a wall at the rate of n discs per minute. The force associated with these discs, in new tons, would be
A)
\[\frac{Mn}{60}\] done
clear
B)
\[60\,mn\] done
clear
C)
\[\frac{M}{60\,n}\] done
clear
D)
\[\frac{n}{60M}\] done
clear
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question_answer27)
If action and reaction were to act on the same body, then
A)
Resultant would be zero done
clear
B)
Body would not move at all done
clear
C)
Both [a] and [b] done
clear
D)
None of these done
clear
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question_answer28)
A 40 kg slab rests on a frictionless floor. A 10 kg block rests on top of the slab. The static coefficient of friction between the block and the slab is 0.60 while the kinetic coefficient is 0.40. The 10 kg block is acted upon by horizontal force 100N. If\[\text{g }=\text{ 9}.\text{8 m}/{{\text{s}}^{\text{2}}}\], then resulting acceleration of the slab will be
A)
\[0.\text{98 m}/{{\text{s}}^{\text{2}}}\] done
clear
B)
\[\text{1}.\text{47 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
\[\text{1}.\text{52 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
\[\text{6}.\text{1 m}/{{\text{s}}^{\text{2}}}\] done
clear
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question_answer29)
A rear side of a truck is open and a box of mass 20 kg is placed on the truck 4 metres away from the open end. \[\mu =0.15\] and\[\text{g }=\text{ 1}0\text{ m}/{{\text{s}}^{\text{2}}}\]. The truck starts from rest with an acceleration of \[\text{2 m}/{{\text{s}}^{\text{2}}}\]on a straight road. The box will fall off the truck when it is at a distance from the starting point equal to
A)
4 metres done
clear
B)
8 metres done
clear
C)
16 metres done
clear
D)
32 metres done
clear
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question_answer30)
A shell is fired from a cannon with a velocity u at an angle \[\theta \] with the horizontal direction. At the highest point in its path, it explodes into two pieces of equal mass. One of the pieces retraces its path of the cannon. Speed of the other piece immediately after the explosion is
A)
\[3\,v\,\cos \,\theta \] done
clear
B)
\[2\,v\,\cos \,\theta \] done
clear
C)
\[\frac{3}{2}\,v\,\cos \,\theta \] done
clear
D)
\[\frac{\sqrt{3}}{2}\,v\,\cos \,\theta \] done
clear
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question_answer31)
A stone is tied to the middle of a string and suspended from one end as shown in the figure. Here S is the stone and 0 is the pint of suspension.
(i) If you give a sharp jerk at P, the string will break
A)
Below the stone done
clear
B)
At the point P itself done
clear
C)
From above the stone done
clear
D)
Nothing can be decided done
clear
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question_answer32)
A stone is tied to the middle of a string and suspended from one end as shown in the figure. Here S is the stone and 0 is the pint of suspension.
(ii) If we increase the pull at P gradually, the string will break
A)
Below the stone done
clear
B)
At the point P itself done
clear
C)
Above the stone done
clear
D)
Nothing can be decided done
clear
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question_answer33)
The combined effect of mass and velocity is taken into account by a physical quantity called
A)
Torque done
clear
B)
Moment of force done
clear
C)
Momentm done
clear
D)
Moment of momentum done
clear
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question_answer34)
Momentum is a measure of
A)
Weight done
clear
B)
Mass done
clear
C)
Quantity of motion done
clear
D)
Velocity done
clear
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question_answer35)
Momentum has the same units as that of
A)
Impulse done
clear
B)
Torque done
clear
C)
Moment of momentum done
clear
D)
Couple done
clear
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question_answer36)
A ball moving with a velocity u strikes a wall moving toward the ball with a velocity u. An elastic impact lasts for t sec. Then the mean elastic force acting on the ball is
A)
\[\frac{2m\upsilon }{t}\] done
clear
B)
\[\frac{2m(\upsilon +u)}{t}\] done
clear
C)
\[\frac{2m(\upsilon +2u)}{t}\] done
clear
D)
\[\frac{m(\upsilon +2u)}{t}\] done
clear
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question_answer37)
When effort is applied parallel to an inclined frictionless plane making an angle \[\theta \] with the horizontal, then mechanical advantage of the system is
A)
B)
\[\tan \theta \] done
clear
C)
\[\cot \theta \] done
clear
D)
\[\text{cosec }\theta \] done
clear
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question_answer38)
A block is released from rest at the top of a frictionless inclined plane 16 m long. It reaches the bottom 4 sec later. A second block is projected up the plane from the bottom at the instant the block is released in such a way that it returns to the bottom simultaneously with first block. The acceleration of each block on the incline is
A)
\[\text{1 m}/{{\text{s}}^{\text{2}}}\] done
clear
B)
\[\text{2 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
\[\text{4 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
\[\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}}\] done
clear
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question_answer39)
In a tug-of-war between the teams A and B, the rope breakes at a point which is nearer to A. Then
A)
A has applied more force done
clear
B)
B has applied more force done
clear
C)
A and B both have applied same force done
clear
D)
None has applied any force done
clear
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question_answer40)
A rocket works on the which law of motion?
A)
First law done
clear
B)
Second law done
clear
C)
Third law done
clear
D)
None of these done
clear
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question_answer41)
The total mass of an elevator, with a 80 kg man in it, is 1000 kg. This elevator moving upward with a speed of 8 m/s is brought to rest over a distance 16 m. Then tension T in the cable supporting elevator is
A)
3200 N done
clear
B)
5400 N done
clear
C)
6500 N done
clear
D)
7800 N done
clear
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question_answer42)
A body moves along circular path of radius 10 m and the coefficient of friction is 0.5. What should be its angular velocity in rad/sec if it is not to slip from the surface?\[\left( \text{g }=\text{ 9}.\text{8 m}/{{\text{s}}^{\text{2}}} \right)\]
A)
0.1 done
clear
B)
0.7 done
clear
C)
5 done
clear
D)
10 done
clear
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question_answer43)
An insect is crawling up a fixed hemispherical bowl of radius R. If the coefficient of friction is 1/3, then the height upto which insect can crawl is
A)
2 % of R done
clear
B)
3 % of R done
clear
C)
4 % of R done
clear
D)
5 % of R done
clear
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question_answer44)
It is difficult to walk on ice because of
A)
Absence of friction done
clear
B)
absence of inertia done
clear
C)
More inertia done
clear
D)
more friction done
clear
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question_answer45)
Newton's which law which defines force?
A)
First law done
clear
B)
Second law done
clear
C)
Third law done
clear
D)
None of these done
clear
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question_answer46)
Internal force
A)
Are always balanced done
clear
B)
Are never balanced done
clear
C)
May or may not be balanced done
clear
D)
None of these done
clear
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question_answer47)
A block of mass 10 kg resting on a horizontal surface is connected by a cord passing over a light frictionless pulley to a hanging block of mass 10 kg as shown in the figure. The coefficient of friction between the block and the surface is 0.5. The acceleration of the system is \[\left( \text{g }==\text{ 1}0\text{ m}/{{\text{s}}^{\text{2}}} \right)\]
A)
\[\text{2}.\text{5 m}/{{\text{s}}^{\text{2}}}\] done
clear
B)
\[0.\text{25 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
\[\text{5 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
\[0.\text{5 m}/{{\text{s}}^{\text{2}}}\] done
clear
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question_answer48)
A rocket of initial mass 6000 kg ejects mass at a constant rate of 16 kg/sec with constant relative speed of 11 km/sec. What is the acceleration of the rocket a minute after the blast? (Neglect gravity)
A)
\[\text{28}.\text{7 m}/{{\text{s}}^{\text{2}}}\] done
clear
B)
\[\text{34}.\text{9 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
\[\text{39}.\text{4 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
\[\text{27}.\text{8 m}/{{\text{s}}^{\text{2}}}\] done
clear
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question_answer49)
A 6000 kg rocket is set for vertical firing. If the exhaust speed is 1000 m/s, how much gas must be ejected each second to supply the thrust needed to overcome the weight of the rocket?
A)
22.2 m/s done
clear
B)
37.6 kg/sec done
clear
C)
58.8 kg/sec done
clear
D)
None of these done
clear
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question_answer50)
Friction between any two objects in due to
A)
Attraction between them done
clear
B)
Repulsion between them done
clear
C)
Some adhesive forces between them done
clear
D)
Irregularities on the surfaces done
clear
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question_answer51)
Fuel is consumed at the rate of 100 kg/sec in a rocket. The exhaust gases are ejected at a speed of \[\text{4}.\text{5 }\times \text{ 1}{{0}^{-\text{4}}}\text{ m}/\text{s}\]. Then the thrust experienced by he rocket is
A)
\[\text{4}.\text{5 x 1}{{0}^{\text{6}}}\text{ N}\] done
clear
B)
\[\text{5}.\text{5 x 1}{{0}^{\text{6}}}\text{ N}\] done
clear
C)
\[\text{3}.\text{5 x 1}{{0}^{\text{6}}}\text{ N}\] done
clear
D)
\[\text{6}.\text{72 x 1}{{0}^{\text{6}}}\text{ N}\] done
clear
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question_answer52)
When a body is stationary
A)
There is no force acting on it done
clear
B)
The forces acting on it are not in contact with it done
clear
C)
The combination of force acting on it balance each other done
clear
D)
The body in vacuum done
clear
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question_answer53)
When a body is in translatory equilibrium
A)
The body is definitely at rest done
clear
B)
The body is definitely in the state of uniform motion done
clear
C)
The body will be either at rest or in the state or uniform motion done
clear
D)
None of these done
clear
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question_answer54)
A body is said to be under balanced forces when the resultant force acting on the body is
A)
Unity done
clear
B)
zero done
clear
C)
Infinite done
clear
D)
none of these done
clear
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question_answer55)
The SI unit offered is
A)
Dyne done
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B)
gram-weight done
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C)
Newton done
clear
D)
None of these done
clear
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question_answer56)
1 dyne is equal to
A)
980 gwt done
clear
B)
\[\frac{1}{980}kg\] gwt done
clear
C)
980 kg wt done
clear
D)
none of these done
clear
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question_answer57)
When a constant force is applied to a body, it moves with uniform
A)
Acceleration done
clear
B)
velocity done
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C)
Speed done
clear
D)
momentum done
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question_answer58)
The ratio of force and acceleration is
A)
Velocity done
clear
B)
impulse done
clear
C)
Momentum done
clear
D)
none of these done
clear
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question_answer59)
When a force of 1 newton acts on a mass of 1 kg that is able to move freely, the object moves with a
A)
Speed of 1 \[\text{m}{{\text{s}}^{\text{-1}}}\] done
clear
B)
Acceleration of 1 \[\text{m}{{\text{s}}^{\text{-2}}}\] done
clear
C)
Speed of 1 k \[\text{m}{{\text{s}}^{\text{-1}}}\] done
clear
D)
None of these done
clear
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question_answer60)
Passengers standing in a bus are thrown outwards when the bus takes a sudden turn,
A)
Outward pull on them done
clear
B)
Inertia done
clear
C)
Change in momentum done
clear
D)
Change in acceleration done
clear
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question_answer61)
When a net force acts on an object, then the object will accelerate in the direction of force with an acceleration proportional to the
A)
Force on the object done
clear
B)
Velocity of the object done
clear
C)
Mass of the object done
clear
D)
Inertia of the object done
clear
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question_answer62)
kg \[\text{m}{{\text{s}}^{\text{-1}}}\]is the SI unit of
A)
Impulse done
clear
B)
force done
clear
C)
Angular velocity done
clear
D)
none of these done
clear
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question_answer63)
For a particle moving along a circular path with a constant speed, the acceleration is constant in
A)
Magnitude done
clear
B)
Direction done
clear
C)
Both magnitude and direction done
clear
D)
Neither magnitude nor direction done
clear
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question_answer64)
Friction is a/an
A)
Self-adjusting force done
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B)
Necessary evil done
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C)
Important force in daily life done
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D)
All of these done
clear
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question_answer65)
Any solid will sink in water if its relative density is .....unity
A)
less than done
clear
B)
equal to done
clear
C)
Greater than done
clear
D)
none of these done
clear
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question_answer66)
A cannon after firing recoils due to
A)
Conservation of energy done
clear
B)
Backward thrust of gases produced done
clear
C)
Newton's first law of motion done
clear
D)
Newton's third law of motion done
clear
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question_answer67)
If a man of weight W is standing in a lift moving upward with an acceleration a, then apparent weight of the man will be
A)
\[W\left( 1+\frac{a}{g} \right)\] done
clear
B)
\[W\left( 1-\frac{a}{g} \right)\] done
clear
C)
\[W\left( 1-\frac{{{a}^{2}}}{{{g}^{2}}} \right)\] done
clear
D)
none of these done
clear
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question_answer68)
The density of water is
A)
\[\text{1}{{0}^{-\text{3}}}\text{ kg}{{\text{m}}^{-\text{3}}}\] done
clear
B)
\[\text{1}{{0}^{-2}}\text{ kg}{{\text{m}}^{-\text{3}}}\] done
clear
C)
\[\text{1}{{0}^{2}}\text{ kg}{{\text{m}}^{-\text{3}}}\] done
clear
D)
\[\text{1}{{0}^{3}}\text{ kg}{{\text{m}}^{-\text{3}}}\] done
clear
View Solution play_arrow
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question_answer69)
If a body of mass M collides against a wall with velocity V and rebounds with the same speed, then its change of momentum will be
A)
Zero done
clear
B)
MV done
clear
C)
2 MV done
clear
D)
\[-2MV\] done
clear
View Solution play_arrow
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question_answer70)
A machine gun fires \[n\] bullets per second and the mass of each bullet is m. If speed of bullets is u, then force exerted on the machine gun will be
A)
\[mng\] done
clear
B)
\[mn\upsilon \] done
clear
C)
\[mn\upsilon g\] done
clear
D)
\[\frac{mn\upsilon }{g}\] done
clear
View Solution play_arrow
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question_answer71)
Buoyant force depends on the
A)
Depth of a liquid done
clear
B)
Density of liquid done
clear
C)
Colour of a liquid done
clear
D)
None of these done
clear
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question_answer72)
If a block has been placed an inclined plane having slope angle \[\theta \]such that the block slides down the plane at a constant speed, then coefficient of kinetic friction will be
A)
\[\sin \,\theta \] done
clear
B)
\[\cos \,\theta \] done
clear
C)
\[g\] done
clear
D)
\[\tan \,\theta \] done
clear
View Solution play_arrow
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question_answer73)
If \[{{\mu }_{\kappa }}\]is coefficient of kinetic friction and \[{{\mu }_{s}}\] is coefficient of static friction, then
A)
\[{{\mu }_{\kappa }}<{{\mu }_{s}}\] done
clear
B)
\[{{\mu }_{s}}<{{\mu }_{\kappa }}\] done
clear
C)
\[{{\mu }_{\kappa }}={{\mu }_{s}}\] done
clear
D)
\[{{\mu }_{s}}\le {{\mu }_{\kappa }}\] done
clear
View Solution play_arrow
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question_answer74)
Vehicles are streamlined to reduce
A)
Static friction done
clear
B)
kinetic friction done
clear
C)
Fluid friction done
clear
D)
sliding friction done
clear
View Solution play_arrow
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question_answer75)
Relation between coefficient of friction \[\mu \] and angle of friction is
A)
\[\mu =\sin \theta \] done
clear
B)
\[\mu =\cos \theta \] done
clear
C)
\[\mu =\tan \theta \] done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer76)
Fluid friction
A)
Is independent of velocity done
clear
B)
Increases with velocity done
clear
C)
Decreases with velocity done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer77)
The ratio of SI units to CGS unit of density is
A)
\[\text{1}{{0}^{\text{3}}}\] done
clear
B)
\[\text{1}{{0}^{\text{2}}}\] done
clear
C)
\[\text{1}{{0}^{-\text{2}}}\] done
clear
D)
\[\text{1}{{0}^{-\text{3}}}\] done
clear
View Solution play_arrow
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question_answer78)
Rolling friction
A)
is independent of velocity done
clear
B)
Varies with velocity done
clear
C)
Increases with velocity done
clear
D)
Decreases with velocity done
clear
View Solution play_arrow
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question_answer79)
Frictional force increases when surfaces in contact are made very smooth, because of
A)
Molecular force done
clear
B)
Decrease in surface area done
clear
C)
Decrease in irregularities done
clear
D)
Increase in area done
clear
View Solution play_arrow
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question_answer80)
Newton's first law of motion defines
A)
Both inertia and force done
clear
B)
Only inertia done
clear
C)
Only force done
clear
D)
Nothing done
clear
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question_answer81)
Newton's second law of motion measures
A)
Inertia done
clear
B)
momentum done
clear
C)
Impulse done
clear
D)
force done
clear
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question_answer82)
When a man in a boat in river jumps from it on river shore, the boat moves
A)
Forward done
clear
B)
Backward done
clear
C)
To right side done
clear
D)
To left side done
clear
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question_answer83)
When a man sitting on a chair tries to lift himself by applying a force on the chair,
A)
He cannot lift on the chair done
clear
B)
He can lift easily done
clear
C)
He can lift himself but very little done
clear
D)
None of the above done
clear
View Solution play_arrow
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question_answer84)
A pilot wants to fly his aeroplane in atmosphere free space
A)
He cannot do it done
clear
B)
He can do it easily done
clear
C)
He can do it but with difficulty done
clear
D)
None of the above done
clear
View Solution play_arrow
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question_answer85)
A flying jet plane gets reaction from
A)
Gravity done
clear
B)
Atmosphere done
clear
C)
Gravity and atmosphere done
clear
D)
Gases ejected from behind done
clear
View Solution play_arrow
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question_answer86)
Every action has reaction. These action-reaction are
A)
Equal, opposite and acting on the same body done
clear
B)
Equal, in the same direction and acting on same body done
clear
C)
Equal, opposite and acting on different bodies done
clear
D)
Equal, in same direction and acting on different bodies. done
clear
View Solution play_arrow
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question_answer87)
When will a body under the action of several forces have zero acceleration?
A)
When the vector sum of all the forces acting on the body is zero. done
clear
B)
When a body is very heavy done
clear
C)
When the body is very light done
clear
D)
When the body is a point body done
clear
View Solution play_arrow
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question_answer88)
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 moving with the same velocity is
A)
\[8\,N\] done
clear
B)
\[ON\] done
clear
C)
\[2\,\times \,10{{\,}^{4}}\,N\] done
clear
D)
\[\frac{1}{2}N\] done
clear
View Solution play_arrow
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question_answer89)
A ball of mass 0-1 kg is thrown against a wall. It strikes the wall normally with a velocity of 30 \[\text{m}{{\text{s}}^{\text{-1}}}\]and rebounds from there with a velocity of 20\[\text{m}{{\text{s}}^{\text{-1}}}\]. The impulse of the force exerted by the ball on the wall is
A)
0.5 Ns done
clear
B)
50 Ns done
clear
C)
5 Ns done
clear
D)
1 Ns done
clear
View Solution play_arrow
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question_answer90)
A body of mass m moving with a constant velocity V hits another body of the same mass moving with the same velocity v but in the opposite direction and sticks to it. The velocity of the compound body after collision is
A)
V done
clear
B)
2v done
clear
C)
Zero done
clear
D)
\[\frac{\upsilon }{2}\] done
clear
View Solution play_arrow
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question_answer91)
In which of the following cases force may not be required to keep the
A)
particle going on the circle done
clear
B)
Particle going along a straight line done
clear
C)
Momentum of the particle constant done
clear
D)
Acceleration of the particle constant done
clear
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question_answer92)
A bullet of mass a and velocity b is fired into a large block of wood of mass c, the final velocity of the system is
A)
\[\frac{b}{c+b}\] done
clear
B)
\[\frac{a+b}{c}a\] done
clear
C)
\[\frac{a}{a+c}a\] done
clear
D)
\[\frac{a+c}{a}b\] done
clear
View Solution play_arrow
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question_answer93)
A force of 12 N gives an object an acceleration of\[\text{4 m}/{{\text{s}}^{\text{2}}}\]. The force required to give it an acceleration of \[\text{1}0\text{ m}/{{\text{s}}^{\text{2}}}\]is
A)
15 N done
clear
B)
20 N done
clear
C)
25 N done
clear
D)
30 N done
clear
View Solution play_arrow
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question_answer94)
A weight of 290 N and another 200 N are suspended by a rope on either side of a frictionless pulley. The acceleration of each weight is
A)
\[\text{1}\text{.5 m}/{{\text{s}}^{\text{2}}}\] done
clear
B)
\[\text{1}\text{.8 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
\[\text{2}\text{.2 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
\[\text{2}\text{.5 m}/{{\text{s}}^{\text{2}}}\] done
clear
View Solution play_arrow
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question_answer95)
Two boxes, one of mass 20 kg and the other of mass 40 kg, are sliding down a frictionless inclined plane that makes an angle of \[30{}^\circ \] with the horizontal. The respective acceleration in \[\text{m}/{{\text{s}}^{\text{2}}}\] are
A)
\[\text{9}\text{.8},\text{9}\text{.8}\] done
clear
B)
\[\text{4}\text{.9},\text{9}\text{.8}\] done
clear
C)
\[\text{9}\text{.8},\text{4}\text{.9}\] done
clear
D)
\[\text{4}\text{.9},\text{4}\text{.9}\] done
clear
View Solution play_arrow
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question_answer96)
Two masses, each equal to m, are attached to one another by a massless string passing over a smooth pulley. The tension in the string is
A)
\[mg\] done
clear
B)
\[2m\] done
clear
C)
\[\frac{mg}{2}\] done
clear
D)
Zero done
clear
View Solution play_arrow
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question_answer97)
What force should be applied on a 5 kg body s that it has a downward acceleration of\[\text{4m}/{{\text{s}}^{\text{2}}}\]?
A)
69 N upwards done
clear
B)
69 N downwards done
clear
C)
29 N upwards done
clear
D)
29 N downwards done
clear
View Solution play_arrow
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question_answer98)
A body rolling freely on the surface of the earth eventually comes to rest because
A)
It has mass done
clear
B)
It suffers friction done
clear
C)
It has inertia of rest done
clear
D)
It has momentum done
clear
View Solution play_arrow
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question_answer99)
A body of mass 50 kg acquires a speed of 20 m/s under a force of 100 n in time
A)
5 s done
clear
B)
10 s done
clear
C)
15 s done
clear
D)
20 s done
clear
View Solution play_arrow
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question_answer100)
The mass of balloon and its contents is M It is descending with an acceleration a. By how much the mass should be decreased, keeping the volume constant, so that the balloon starts ascending with the same acceleration?
A)
\[\frac{a}{a+g}M\] done
clear
B)
\[\frac{g}{a+g}M\] done
clear
C)
\[\frac{2a}{a+g}M\] done
clear
D)
\[\frac{2g}{a+g}M\] done
clear
View Solution play_arrow
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question_answer101)
Two blocks A and B, having masses m, and m respectively, are placed in contact on a smooth horizontal surface. A force F is applied horizontally on A. The contact force between A and B is
A)
\[\frac{{{m}_{1}}}{{{m}_{2}}}F\] done
clear
B)
\[\frac{{{m}_{2}}}{{{m}_{1}}}F\] done
clear
C)
\[\frac{{{m}_{1}}F}{{{m}_{1}}+{{m}_{2}}}\] done
clear
D)
\[\frac{{{m}_{2}}F}{{{m}_{1}}+{{m}_{2}}}\] done
clear
View Solution play_arrow
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question_answer102)
A block of mass 9 kg, lying on a frictionless table is connected to a block of mass 1 kg by means of a string which passes over a frictionless pulley as shown. The tension in the string is \[\left( \text{g}=\text{1}0\text{ m}/{{\text{s}}^{\text{2}}} \right)\]
A)
1N done
clear
B)
4N done
clear
C)
7N done
clear
D)
9N done
clear
E)
None of these done
clear
View Solution play_arrow
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question_answer103)
The minimum acceleration with which a fireman slide down a rope of breaking strength two-third of his weight is
A)
Zero done
clear
B)
\[\frac{g}{3}\] done
clear
C)
\[\frac{2g}{3}\] done
clear
D)
\[g\] done
clear
View Solution play_arrow
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question_answer104)
A disc of mass 10 g is kept floating horizontally by throwing 10 marbles per second against it from below. The marbles strike the disc normally and rebound downwards with the same speed If the mass of each marble is 5 g, the velocity with which the marbles are striking the disc is\[(g=9.8\,m/{{s}^{2}})\].
A)
0.98 m/s done
clear
B)
9.8 m/s done
clear
C)
1.96 m/s done
clear
D)
19.6 m/s done
clear
View Solution play_arrow
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question_answer105)
A monkey of mass 40 kg climbs on a massless rope of breaking strength 600 N. The rope will break if the monkey \[\left( \text{g}=\text{1}0\text{ m}/{{\text{s}}^{\text{2}}} \right)\]
A)
Climbs up with a uniform speed of 5 m/s done
clear
B)
Climbs up with an acceleration of \[\text{6 m}/{{\text{s}}^{\text{2}}}\] done
clear
C)
Climbs down with an acceleration of \[\text{4 m}/{{\text{s}}^{\text{2}}}\] done
clear
D)
Climbs down with a uniform speed of \[\text{5 m}/\text{s}\] done
clear
View Solution play_arrow
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question_answer106)
A body is projected up a \[40{}^\circ \] rough inclined plane. If the coefficient of friction is 0-5, then the retardation of the block is
A)
\[\frac{g}{2\sqrt{2}}\] done
clear
B)
\[\frac{g}{\sqrt{2}}\] done
clear
C)
\[\frac{3g}{2\sqrt{2}}\] done
clear
D)
\[\frac{g}{2}\] done
clear
View Solution play_arrow
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question_answer107)
A block of mass 5 kg is placed on a rough inclined plane. The inclination of the lane is gradually increased till the block just begin to slide down The inclination of the plane is then 3 in 5 The coefficient of friction between the block and the plane is \[\left( \text{g}=\text{ 1}0\text{ m}/{{\text{s}}^{\text{2}}} \right)\]
A)
3/5 done
clear
B)
3/4 done
clear
C)
4/5 done
clear
D)
2/3 done
clear
View Solution play_arrow
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question_answer108)
In the above question, the minimum force required to move the block up the plane at this inclination is
A)
30 N done
clear
B)
40 N done
clear
C)
60 N done
clear
D)
120 N done
clear
View Solution play_arrow
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question_answer109)
A body rests on a rough horizontal plane. A force is applied to the body directed towards the plane at an angle \[\phi \]with the vertical. The body can be moved along the plane.
A)
Only \[\phi \]is more than the angle of friction done
clear
B)
Only \[\phi \] is less than the angle of friction done
clear
C)
Only \[\phi \] is equal to the angle of friction done
clear
D)
For all values of \[\phi \] done
clear
View Solution play_arrow
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question_answer110)
A particle of mass 100 g is suspended from a light string. The string is moved [a] Upwards, and [b] Downwards with an acceleration of\[\text{5 m}/{{\text{s}}^{\text{2}}}\]. If \[{{T}_{u}}\] and \[{{T}_{d}}\] are the tension in the string during upward and downward motion respectively, then \[{{T}_{u}}-{{T}_{d}}\] is equal to
A)
1N done
clear
B)
0.5 N done
clear
C)
0.98 N done
clear
D)
1.96 N done
clear
View Solution play_arrow
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question_answer111)
The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as
A)
\[m\left( 1-\frac{a}{g} \right)\] done
clear
B)
\[\left( 1+\frac{a}{g} \right)\] done
clear
C)
\[m\] done
clear
D)
Zero done
clear
View Solution play_arrow
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question_answer112)
A string is compressed between two toy-carts of masses \[{{m}_{1}}\] and \[{{m}_{2}}\]. When the toy-carts are released, the spring exerts on each equal and opposite average forces for the same time\[t\]. If the coefficient of friction \[\mu \] between the ground and the carts are equal, then the displacement of the two toy-carts are in the ratio
A)
\[\frac{{{S}_{1}}}{{{S}_{2}}}=\frac{{{m}_{2}}}{{{m}_{1}}}\] done
clear
B)
\[\frac{{{S}_{1}}}{{{S}_{2}}}=\frac{{{m}_{1}}}{{{m}_{2}}}\] done
clear
C)
\[\frac{{{S}_{1}}}{{{S}_{2}}}={{\left( \frac{{{m}_{2}}}{{{m}_{1}}} \right)}^{2}}\] done
clear
D)
\[\frac{{{S}_{1}}}{{{S}_{2}}}=-{{\left( \frac{{{m}_{2}}}{{{m}_{1}}} \right)}^{2}}\] done
clear
View Solution play_arrow
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question_answer113)
A block of mass 1 kg moving with a speed of \[\text{2 m}{{\text{s}}^{\text{-1}}}\]collides with and sticks to another block of mass 2 kg which was initially at rest. After the collision
A)
The momentum of the system is less than \[\text{2}\,\text{kg}\,\text{m}{{\text{s}}^{-\text{1}}}\]9 done
clear
B)
The kinetic energy of the system is\[\frac{2}{3}J\] done
clear
C)
The kinetic energy of the system is \[2J\] done
clear
D)
None of these done
clear
View Solution play_arrow
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question_answer114)
A bullet of mass \[{{m}_{1}}\] is fired into a block mass \[{{m}_{2}}\] suspended like a pendulum. The block, initially at rest, is raised to a height h, after the impact. The velocity of the bullet is
A)
\[\left( 1+\frac{{{m}_{1}}}{{{m}_{2}}} \right)\sqrt{gh}\] done
clear
B)
\[\frac{{{m}_{1}}}{{{m}_{2}}}\sqrt{2gh}\] done
clear
C)
\[\left( 1+\frac{{{m}_{1}}}{{{m}_{2}}} \right)\sqrt{2gh}\] done
clear
D)
\[\left( 1+\frac{{{m}_{2}}}{{{m}_{1}}} \right)\sqrt{2gh}\] done
clear
View Solution play_arrow
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question_answer115)
Force of friction between the floor and a wooden block of mass M and area of surface A is F. Force of friction between the floor and a block of mass 2 M and area of surface A will be
A)
2 F done
clear
B)
F done
clear
C)
\[\frac{F}{2}\] done
clear
D)
\[\sqrt{2}F\] done
clear
View Solution play_arrow
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question_answer116)
A diwali rocket is ejecting 0.05 kg of gases per second at a velocity of 400 m/sec. The accelerating force on the rocket is
A)
20 dynes done
clear
B)
20 Newtons done
clear
C)
20 kg wt done
clear
D)
10 Newtons done
clear
View Solution play_arrow
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question_answer117)
A bullet fired into a wall loses half of its velocity after penetrating 3 cm. Further it can penetrate a maximum of
A)
3 cm done
clear
B)
2 cm done
clear
C)
1cm done
clear
D)
0.5cm done
clear
View Solution play_arrow
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question_answer118)
A body of mass 100 g is sliding from an inclined plane of inclination \[30{}^\circ \]. What is the frictional force experienced, if \[\mu =1.7\]?
A)
\[1.7\times \sqrt{2}\times \frac{1}{\sqrt{3}}N\] done
clear
B)
\[1.7\times \sqrt{3}\times \frac{1}{2}N\] done
clear
C)
\[1.7\times \sqrt{3}N\] done
clear
D)
\[1.7\times \sqrt{2}\times \frac{\sqrt{2}}{\sqrt{3}}N\] done
clear
View Solution play_arrow
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question_answer119)
Which of the following is not a perfectly inelastic collision?
A)
Striking of two glass balls done
clear
B)
A bullet striking a bag of sand done
clear
C)
An electron captured by a proton done
clear
D)
A man jumping into a moving cart done
clear
View Solution play_arrow
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question_answer120)
A plank, 8 m long, has one end 1 m higher than the other. What minimum force parallel to the plank will be necessary to push a box up it, the box and its contents having a mass of 100 kg and the coefficient of sliding friction between it and the plank being 0.3 ?
A)
50.2 kgf done
clear
B)
25.5 kgf done
clear
C)
75.0 kgf done
clear
D)
42.3 kgf done
clear
View Solution play_arrow
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question_answer121)
A truck and a car moving with same kinetic energy are stopped by equal retarding force. Which of them will be stopped in shorter distance?
A)
Truck done
clear
B)
Car done
clear
C)
Both simultaneously done
clear
D)
Data not sufficient done
clear
View Solution play_arrow
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question_answer122)
A man weighing 80 kg is standing in a trolley weighing 320 kg. The trolley is resting on frictionless horizontal rails. If the man starts walking on the trolley with a speed of 1 m/s, then after 4 sec his displacement relative to the ground will be
A)
5 m done
clear
B)
4.8 m done
clear
C)
3.2m done
clear
D)
3.0 m done
clear
View Solution play_arrow
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question_answer123)
A jet of water (density \[\rho \]) with a cross-sectional area a is striking against a wall at an angle \[\theta \] to the normal and rebounds elastically. If the velocity of water in the jet is v, the normal force acting on the wall is
A)
\[2\,\,a{{\upsilon }^{2\,\,}}\,p\,\,\cos \,\theta \] done
clear
B)
\[a{{\upsilon }^{2\,\,}}\,p\,\,\cos \,\theta \] done
clear
C)
\[2\,\,\,a\upsilon \,\,p\,\,\cos \,\theta \] done
clear
D)
\[a\upsilon \,\,p\,\,\cos \,\theta \] done
clear
View Solution play_arrow
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question_answer124)
A bucket containing water of depth 15 cm is kept in a lift which is moving upwards with an acceleration 2 g. The pressure at the bottom of the bucket is
A)
\[\text{1}0\text{ g dyne c}{{\text{m}}^{\text{-2}}}\] done
clear
B)
\[\text{2 dyne c}{{\text{m}}^{\text{-2}}}\] done
clear
C)
\[\text{4}0\text{ g dyne c}{{\text{m}}^{\text{-2}}}\] done
clear
D)
\[\text{45 g dyne c}{{\text{m}}^{\text{-2}}}\] done
clear
View Solution play_arrow
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question_answer125)
Two masses m and 2m are attached with each other by a rope passing over a frictionless and massless pulley. If the pulley is accelerated upwards with an acceleration a, what is the value of T ?
A)
\[\frac{g+a}{3}\] done
clear
B)
\[\frac{g-a}{3}\] done
clear
C)
\[\frac{4m(g+a)}{3}\] done
clear
D)
\[\frac{m(g-a)}{3}\] done
clear
View Solution play_arrow
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question_answer126)
A body of mass 2 kg is initially moving with a velocity of 4 m/sec. Now a force of 1.25 Newtons acts for 8 sec. Then a force of 2.5 N acts for 8 sec. The final velocity of the body is
A)
12.55 m/sec done
clear
B)
17 m/sec done
clear
C)
19 m/sec done
clear
D)
25 m/sec done
clear
View Solution play_arrow
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question_answer127)
A body is freely released from point A so that it slides down the smooth inclined plane AB and then along the rough horizontal surface BC and comes to point C with 4 m/sec. Then the coefficient of friction over the rough surface is
A)
0.2 done
clear
B)
0.4 done
clear
C)
0.65 done
clear
D)
0.75 done
clear
View Solution play_arrow
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question_answer128)
Three bodies nip \[{{m}_{1}},{{m}_{2}}\] and \[{{m}_{3}}\]nip of mass 10 kg, 20 kg and 30 kg respectively are lying on a frictionless horizontal table and are connected by strings as shown in the figure. These are pulled towards the right with a force of 60 N. Then the tension \[{{T}_{1}},\] and \[{{T}_{2}},\] will respectively be
A)
10 N, 20 N done
clear
B)
20 N, 20 N done
clear
C)
10 N, 50 N done
clear
D)
10 N, 30 N done
clear
View Solution play_arrow
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question_answer129)
An alpha-particle is emitted by U238 nucleus with a speed of \[\text{1}.\text{5 x 1}{{0}^{\text{7}}}\] m/sec. The recoil speed of the remaining nucleus will be
A)
\[\text{2}.\text{4 x 1}{{0}^{\text{5}}}\text{ m}/\text{sec}\] done
clear
B)
\[0.\text{24 x 1}{{0}^{\text{5}}}\text{ m}/\text{sec}\] done
clear
C)
\[\text{24 x 1}{{0}^{\text{5}}}\text{ m}/\text{sec}\] done
clear
D)
\[\text{245 x 1}{{0}^{\text{5}}}\text{ m}/\text{sec}\] done
clear
View Solution play_arrow
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question_answer130)
Two freely hanging weights, each having a mass of 60 gm, are connected by a light thread which passes over a fixed pulley. The mass of the pulley and frictional losses are negligible. If a 10 gm weight is now added to one of the weights, its downward acceleration, in\[\text{cm}/\text{se}{{\text{c}}^{\text{2}}}\], will be approximately
A)
32 done
clear
B)
80 done
clear
C)
106 done
clear
D)
980 done
clear
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question_answer131)
A cricket ball of mass 150 gram moving with a velocity of 12 m/s strikes against the bat. It renounces with a velocity of 20 m/s. The ball remains in touch with the bat for 0.01 second. The average force applied by the bat on the ball is
A)
840 Newton done
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B)
480 Newton done
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C)
804 Newton done
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D)
408 Newton done
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question_answer132)
Action and reaction act on
A)
Same body in opposite directions done
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B)
Same body in the same direction done
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C)
Different bodies in opposite directions done
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D)
Different bodies but in the same direction done
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question_answer133)
A block of mass m, attached to a spring of spring constant k, oscillates on a smooth horizontal table. The other end of the spring is fixed to a wall. If it has a speed v when the spring is at its natural length, how far will it move on the table before coming to an instantaneous rest
A)
\[\sqrt{\frac{\upsilon m}{k}}\] done
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B)
\[\sqrt{\frac{\upsilon k}{m}}\] done
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C)
\[u\sqrt{\frac{k}{m}}\] done
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D)
\[u\sqrt{\frac{m}{k}}\] done
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question_answer134)
It is easier to draw up wooden block along an inclined plane than have it up vertically, principally because
A)
The friction is reduced done
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B)
The mass becomes smaller done
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C)
Only a part of weight has to be overcome done
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D)
g becomes smaller. done
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question_answer135)
A ball of mass 0.2 kg moves with a velocity of 20 m/s and it stops in 0.1 s, then the force on the ball is
A)
40 N done
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B)
20 N done
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C)
4N done
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D)
2 N done
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question_answer136)
What maximum horizontal force can be applied to the lower block so that the two blocks move without separation ?
A)
\[(M+m)({{\mu }_{1}}+{{\mu }_{2}})g\] done
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B)
\[(M-m)({{\mu }_{1}}+{{\mu }_{2}})g\] done
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C)
\[(M+m)({{\mu }_{1}}-{{\mu }_{2}})g\] done
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D)
\[(M-m)({{\mu }_{1}}-{{\mu }_{2}})g\] done
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question_answer137)
Which one of the following statement does not hold good when two balls of masses \[{{m}_{1}}\] and \[{{m}_{2}}\] undergo elastic collision?
A)
When \[{{m}_{1}}<{{m}_{2}}\] and \[{{m}_{2}}\] at rest, there will be maximum transfer of momentum. done
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B)
When \[{{m}_{1}}={{m}_{2}}\] and \[{{m}_{2}}\] at rest, there will be maximum transfer of K.E. done
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C)
When collision is oblique and \[{{m}_{2}}\] at rest with \[{{m}_{1}}={{m}_{2}}\], after collision the ball moves in opposite direction. done
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D)
None of these done
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question_answer138)
A boy sitting on the top most berth in the compartment of a train which is just joint to stop on a railway station, drops an apple aiming at the open hand of his brother situated vertically below his hands at a distance of about 2m. The apple will fall
A)
In the hand of his brother. done
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B)
Slightly away from the hands of his brother in the direction of motion of the train. done
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C)
Slightly away from the hands of his brother in the direction opposite to the direction of motion of the train. done
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D)
None of the above. done
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question_answer139)
A stretching force of 1000 Newton is applied at one end of a spring balance and an equal stretching force is applied at the other end at the same time. The reading of the balance will be
A)
2000 N done
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B)
0 N done
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C)
1000N done
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D)
500N done
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question_answer140)
Two mass A and B each of mass M are fixed together by a massless spring A force F acts on the mass B as shown in figure. At the instant shown, the mass A has acceleration a. What is the acceleration of mass B ?
A)
\[\left( \frac{F}{M} \right)-a\] done
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B)
\[a\] done
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C)
\[-a\] done
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D)
\[\left( \frac{F}{M} \right)\] done
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question_answer141)
A block of mass 2 kg is placed on the floor. The coefficient of static friction is 0.4. If a force of 2.8 N is applied on the block parallel to the floor, the force of friction between the block and floor \[\left( \text{taking g }=\text{ 1}0\text{ m}/\text{se}{{\text{c}}^{\text{2}}} \right)\] is
A)
2.8 N done
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B)
8N done
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C)
2N done
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D)
Zero done
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question_answer142)
A block has been placed on an inclined plane. The slope angle 6 of the plane is such that the block slides down the plane at a constant speed. The coefficient of kinetic friction is equal to
A)
\[\sin \,\,\theta \] done
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B)
\[\cos \,\,\theta \] done
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C)
\[g\] done
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D)
\[\tan \,\,\theta \] done
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question_answer143)
A body of mass 60 kg is dragged with just enough force to start moving on a rough surface with coefficients of static and kinetic frictions 0.5 and 0.4 respectively. On applying the same force, what is the acceleration?
A)
\[0.\text{98 m}/{{\text{s}}^{\text{2}}}\] done
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B)
\[\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}}\] done
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C)
\[0.\text{54 m}/{{\text{s}}^{\text{2}}}\] done
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D)
\[\text{5}.\text{292 m}/{{\text{s}}^{\text{2}}}\] done
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question_answer144)
Pushing force making an angle \[\theta \]to the horizontal is applied on a block of weight W placed on a horizontal table. If the angle of friction is\[\phi \] , the magnitude of force required to move the body is equal to
A)
\[\frac{W\,\cos \phi }{\cos \,(\theta -\phi )}\] done
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B)
\[\frac{W\,\sin \phi }{\cos \,(\theta -\phi )}\] done
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C)
\[\frac{W\,\tan \phi }{\sin (\theta -\phi )}\] done
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D)
\[\frac{W\,\sin \phi }{g\sin (\theta -\phi )}\] done
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E)
None of these done
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question_answer145)
A mass m rest on a horizontal surface. The coefficient of friction between the mass and the surface is p. If the mass is pulled by a force P 3. shown in the figure, the limiting friction between mass and the surface will be
A)
\[\mu \,mg\] done
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B)
\[\mu \,\left[ mg-\left( \frac{\sqrt{3}}{2} \right)F \right]\] done
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C)
\[\mu \,\left[ mg-\left( \frac{F}{2} \right) \right]\] done
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D)
\[\mu \,\left[ mg+\left( \frac{F}{2} \right) \right]\] done
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question_answer146)
A block of mass 0.1 kg is held against a wall by applying a horizontal force of 5 N on the lock. If the coefficient of friction between the block and the wall is 0.5, the magnitude of the frictional force acting on the block is
A)
2.5 N done
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B)
0.98 N done
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C)
4.9 N done
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D)
0.49 N done
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question_answer147)
A free body of mass 8 kg is travelling at 2 metres per second in a straight line. At a certain instant, the body splits into two equal parts due to internal explosion which releases 16 joules of energy. Finally
A)
Both parts continue to move in the same direction as that of the original body. done
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B)
One part comes to rest and the other moves in the same direction as that of the original body. done
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C)
One part comes to rest and the other moves in the direction opposite to that of the original body. done
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D)
one part moves in the same direction and the other in the direction opposite to that of the original body. done
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question_answer148)
Six identical balls are lined up along a straight frictionless groove. Two similar balls moving with speed v along the groove collide with this row on extreme left side end. Then
A)
One ball from the right end will move on with speed \[\varepsilon \upsilon \], all the other remains at rest done
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B)
Two balls from the extreme right will move on the speed u each and the remaining balls will be at rest. done
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C)
All the balls will start moving to the right with. done
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D)
All the six balls originally at rest will moves on with speed \[\frac{\upsilon }{6}\] each and the two incident ball will come to rest. done
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question_answer149)
Two perfectly elastic particles A and B of equal masses travelling along the line joining them with velocity 15 m/s and 10 m/s respectively collide. Their velocities after the elastic collision will be (in m/s) respectively
A)
0 and 25 done
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B)
5 and 20 done
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C)
10 and 15 done
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D)
20 and 5 done
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question_answer150)
When a horse pulls a wagon, the force that causes the horse to move forward is the force
A)
He exerts on the wagon done
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B)
The wagon exerts on him done
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C)
The ground exerts on him done
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D)
He exerts on the ground. done
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question_answer151)
A parachutist of weight W strikes the ground with his legs fixed and comes to rest with an upward acceleration of 3 g. Force exerted by him on the ground during landing is
A)
W done
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B)
2W done
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C)
3W done
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D)
4W done
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question_answer152)
A monkey is descending from the branch of a tree with constant acceleration. If the breaking strength is 75% of the weight of the monkey, the minimum acceleration with which monkey can slide down without breaking the branch is
A)
g done
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B)
\[\frac{3g}{4}\] done
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C)
\[\frac{g}{4}\] done
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D)
\[\frac{g}{2}\] done
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question_answer153)
A car is moving on a straight road with a speed \[{{V}_{0}}\]. If the coefficient of friction between the tyres and the road is p, the distance travelled by the car before it comes to rest is
A)
\[\frac{{{V}_{0}}^{2}}{2\mu g}\] done
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B)
\[\left( \frac{{{V}_{0}}^{2}}{\mu g} \right)\] done
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C)
\[\frac{{{V}_{0}}}{\mu g}\] done
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D)
\[\frac{{{V}_{0}}^{2}}{\mu g}\] done
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question_answer154)
A machine-gun fires 20 bullets per second into a target. Each bullet weight 150 gm and has a speed of 800 m/sec. The force necessary to hold the gun in position is
A)
800 N done
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B)
(6) 1000 N done
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C)
1200 N done
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D)
2400 N done
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E)
None of these done
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question_answer155)
A sphere of mass m moving with a constant velocity u hits another stationary sphere of same mass. If e is the coefficient of restitution, then ratio of velocities of the two spheres after collision will be
A)
\[\frac{1-e}{1+e}\] done
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B)
\[\frac{1+e}{1-e}\] done
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C)
\[\frac{e-1}{1-e}\] done
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D)
\[\frac{e-1}{1+e}\] done
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question_answer156)
A particle moves in the x-y plane under the action of a force \[\overrightarrow{F}\] such that the value of its linear momentum \[\overrightarrow{P}\] at any time t is \[{{p}_{X}}=2\] cos t and the angle \[\theta \] between \[\overrightarrow{F}\] and \[\overrightarrow{P}\] at any time t will be
A)
\[90{}^\circ \] done
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B)
\[0{}^\circ \] done
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C)
\[180{}^\circ \] done
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D)
\[30{}^\circ \] done
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