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question_answer1)
A jet plane flies in the air because [NCERT 1971]
A)
The gravity does not act on bodies moving with high speeds done
clear
B)
The thrust of the jet compensates for the force of gravity done
clear
C)
The flow of air around the wings causes an upward force, which compensates for the force of gravity done
clear
D)
The weight of air whose volume is equal to the volume of the plane is more than the weight of the plane done
clear
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question_answer2)
A player caught a cricket ball of mass 150 gm moving at a rate of 20 m/s. If the catching process be completed in 0.1 s, then the force of the blow exerted by the ball on the hands of the player is [AFMC 1993; CBSE PMT 2001; BHU 2001]
A)
0.3 N done
clear
B)
30 N done
clear
C)
300 N done
clear
D)
3000 N done
clear
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question_answer3)
A rocket has a mass of 100 kg. 90% of this is fuel. It ejects fuel vapours at the rate of 1 kg/sec with a velocity of 500 m/sec relative to the rocket. It is supposed that the rocket is outside the gravitational field. The initial upthrust on the rocket when it just starts moving upwards is [NCERT 1978]
A)
Zero done
clear
B)
500 N done
clear
C)
1000 N done
clear
D)
2000 N done
clear
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question_answer4)
In which of the following cases forces may not be required to keep the [AIIMS 1983]
A)
Particle going in a circle done
clear
B)
Particle going along a straight line done
clear
C)
The momentum of the particle constant done
clear
D)
Acceleration of the particle constant done
clear
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question_answer5)
A wagon weighing 1000 kg is moving with a velocity 50km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is [MP PMT 1994]
A)
2.5 km/hour done
clear
B)
20 km/hour done
clear
C)
40 km/hour done
clear
D)
50 km/hour done
clear
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question_answer6)
If a force of 250 N act on body, the momentum acquired is 125 kg-m/s. What is the period for which force acts on the body [CMEET Bihar 1995]
A)
0.5 sec done
clear
B)
0.2 sec done
clear
C)
0.4 sec done
clear
D)
0.25 sec done
clear
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question_answer7)
A 100 g iron ball having velocity 10 m/s collides with a wall at an angle 30° and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is [CPMT 1997]
A)
10 N done
clear
B)
100 N done
clear
C)
1.0 N done
clear
D)
0.1 N done
clear
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question_answer8)
A ball of mass 150g starts moving with an acceleration of \[20m/{{s}^{2}}\]. When hit by a force, which acts on it for 0.1 sec. The impulsive force is [AFMC 1999; Pb. PMT 2003]
A)
0.5 N-s done
clear
B)
0.1 N-s done
clear
C)
0.3 N-s done
clear
D)
1.2 N-s done
clear
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question_answer9)
A body, whose momentum is constant, must have constant [AIIMS 2000]
A)
Force done
clear
B)
Velocity done
clear
C)
Acceleration done
clear
D)
All of these done
clear
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question_answer10)
The motion of a rocket is based on the principle of conservation of [AFMC 2000]
A)
Mass done
clear
B)
Kinetic energy done
clear
C)
Linear momentum done
clear
D)
Angular momentum done
clear
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question_answer11)
A rope of length 5m is kept on frictionless surface and a force of 5N is applied to one of its end. Find tension in the rope at 1m from this end [RPET 2000]
A)
1 N done
clear
B)
3 N done
clear
C)
4 N done
clear
D)
5 N done
clear
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question_answer12)
An aircraft is moving with a velocity of \[300\,m{{s}^{-1}}.\] If all the forces acting on it are balanced, then [Kerala PMT 2004]
A)
It still moves with the same velocity done
clear
B)
It will be just floating at the same point in space done
clear
C)
It will fall down instantaneously done
clear
D)
It will lose its velocity gradually done
clear
E)
It will explode done
clear
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question_answer13)
A rocket of mass 1000 kg exhausts gases at a rate of 4 kg/sec with a velocity 3000 m/s. The thrust developed on the rocket is [Orissa JEE 2005]
A)
12000 N done
clear
B)
120 N done
clear
C)
800 N done
clear
D)
200 N done
clear
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question_answer14)
The momentum is most closely related to [DCE 2001]
A)
Force done
clear
B)
Impulse done
clear
C)
Power done
clear
D)
K.E. done
clear
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question_answer15)
Rocket engines lift a rocket from the earth surface because hot gas with high velocity [AIIMS 1998; JIPMER 2001, 02]
A)
Push against the earth done
clear
B)
Push against the air done
clear
C)
React against the rocket and push it up done
clear
D)
Heat up the air which lifts the rocket done
clear
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question_answer16)
A man fires a bullet of mass 200 g at a speed of 5 m/s. The gun is of one kg mass. by what velocity the gun rebounds backwards [CBSE PMT 1996; JIPMER 2000]
A)
0.1 m/s done
clear
B)
10 m/s done
clear
C)
1 m/s done
clear
D)
0.01 m/s done
clear
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question_answer17)
A bullet of mass 5 g is shot from a gun of mass 5 kg. The muzzle velocity of the bullet is 500 m/s. The recoil velocity of the gun is [DCE 2004]
A)
0.5 m/s done
clear
B)
0.25 m/s done
clear
C)
1 m/s done
clear
D)
Data is insufficient done
clear
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question_answer18)
A force of 50 dynes is acted on a body of mass 5 g which is at rest for an interval of 3 seconds, then impulse is [AFMC 1998]
A)
\[0.15\times {{10}^{-3}}\,Ns\] done
clear
B)
\[0.98\times {{10}^{-3}}\,Ns\] done
clear
C)
\[1.5\times {{10}^{-3}}\,Ns\] done
clear
D)
\[2.5\times {{10}^{-3}}\,Ns\] done
clear
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question_answer19)
A body of mass M at rest explodes into three pieces, two of which of mass M/4 each are thrown off in perpendicular directions with velocities of 3 m/s and 4 m/s respectively. The third piece will be thrown off with a velocity of [CPMT 1990]
A)
1.5 m/s done
clear
B)
2.0 m/s done
clear
C)
2.5 m/s done
clear
D)
3.0 m/s done
clear
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question_answer20)
The momentum of a system is conserved [CPMT 1982]
A)
Always done
clear
B)
Never done
clear
C)
In the absence of an external force on the system done
clear
D)
None of the above done
clear
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question_answer21)
A body of mass 0.25 kg is projected with muzzle velocity \[100\,m{{s}^{-1}}\] from a tank of mass 100 kg. What is the recoil velocity of the tank [AFMC 1996]
A)
\[5\,m{{s}^{-1}}\] done
clear
B)
\[25\,m{{s}^{-1}}\] done
clear
C)
\[0.5\,m{{s}^{-1}}\] done
clear
D)
\[0.25\,m{{s}^{-1}}\] done
clear
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question_answer22)
A bullet is fired from a gun. The force on the bullet is given by \[F=600-2\times {{10}^{5}}t\], where F is in newtons and t in seconds. The force on the bullet becomes zero as soon as it leaves the barrel. What is the average impulse imparted to the bullet [CBSE PMT 1998]
A)
9 Ns done
clear
B)
Zero done
clear
C)
0.9 Ns done
clear
D)
1.8 Ns done
clear
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question_answer23)
A bullet of mass 0.1 kg is fired with a speed of 100 m/sec, the mass of gun is 50 kg. The velocity of recoil is [AFMC 1995; JIPMER 2000; Pb.PMT 2002]
A)
0.2 m/sec done
clear
B)
0.1 m/sec done
clear
C)
0.5 m/sec done
clear
D)
0.05 m/sec done
clear
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question_answer24)
A bullet mass 10 gm is fired from a gun of mass 1kg. If the recoil velocity is 5 m/s, the velocity of the muzzle is [Orissa JEE 2002]
A)
0.05 m/s done
clear
B)
5 m/s done
clear
C)
50 m/s done
clear
D)
500 m/s done
clear
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question_answer25)
A rocket can go vertically upwards in earth's atmosphere because [CPMT 1980]
A)
It is lighter than air done
clear
B)
Of gravitational pull of the sun done
clear
C)
It has a fan which displaces more air per unit time than the weight of the rocket done
clear
D)
Of the force exerted on the rocket by gases ejected by it done
clear
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question_answer26)
At a certain instant of time the mass of a rocket going up vertically is 100 kg. If it is ejecting 5 kg of gas per second at a speed of 400 m/s, the acceleration of the rocket would be (taking \[g=10\,m/{{s}^{2}})\] [NCERT 1984]
A)
\[20\,m/{{s}^{2}}\] done
clear
B)
\[10\,m/{{s}^{2}}\] done
clear
C)
\[2\,m/{{s}^{2}}\] done
clear
D)
\[1\,m/{{s}^{2}}\] done
clear
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question_answer27)
A jet engine works on the principle of [CPMT 1973; MP PMT 1996]
A)
Conservation of mass done
clear
B)
Conservation of energy done
clear
C)
Conservation of linear momentum done
clear
D)
Conservation of angular momentum done
clear
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