JEE Main & Advanced Physics NLM, Friction, Circular Motion Question Bank

done Second Law of Motion Total Questions - 113

• question_answer1)
  If a bullet of mass 5 gm moving with velocity 100 m /sec, penetrates the wooden block upto 6 cm. Then the average force imposed by the bullet on the block is       [MP PMT 2003]
  A)
                          8300 N             done clear
  B)
                            417 N             done clear
  C)
                          830 N              done clear
  D)
                          Zero done clear
  View Solution play_arrow

• question_answer2)
  Newton's second law gives the measure of [CPMT 1982]            
  A)
                               Acceleration             done clear
  B)
                            Force             done clear
  C)
                          Momentum                  done clear
  D)
                          Angular momentum done clear
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• question_answer3)
  A force of 100 dynes acts on mass of 5 gm for 10 sec. The velocity produced is                                 [MNR 1987]
  A)
                          2 cm/sec             done clear
  B)
                            20 cm/sec             done clear
  C)
                          200 cm/sec                  done clear
  D)
                          2000 cm/sec done clear
  View Solution play_arrow

• question_answer4)
  An object will continue moving uniformly until                                       [CPMT 1975]            
  A)
                          The resultant force acting on it begins to decrease             done clear
  B)
                          The resultant force on it is zero             done clear
  C)
                          The resultant force is at right angle to its rotation             done clear
  D)
                          The resultant force on it is increased continuously done clear
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• question_answer5)
  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 [NCERT 1979; DPMT 2001; MP PMT 2004]            
  A)
                               20 dynes           done clear
  B)
                                        20 N             done clear
  C)
                          22 dynes             done clear
  D)
                            1000 N done clear
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• question_answer6)
  A body of mass 2 kg moving on a horizontal surface with an initial velocity of 4 m/sec comes to rest after 2 sec. If one wants to keep this body moving on the same surface with a velocity of 4 m/sec, the force required is            [NCERT 1977]
  A)
                          8 N                  done clear
  B)
                          4 N             done clear
  C)
                          Zero                 done clear
  D)
                          2 N done clear
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• question_answer7)
  A body of mass 2 kg is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity ?g?, the reading on the spring balance will be                          [NCERT 1977]
  A)
                          2 kg                  done clear
  B)
                          \[(4\times g)\,kg\]             done clear
  C)
                          \[(2\times g)\,kg\]             done clear
  D)
                            Zero             done clear
  View Solution play_arrow

• question_answer8)
  In the above problem, if the lift moves up with a constant velocity of 2 m/sec, the reading on the balance will be [NCERT 1977]            
  A)
                          2 kg                  done clear
  B)
                          4 kg             done clear
  C)
                          Zero                 done clear
  D)
                          1 kg done clear
  View Solution play_arrow

• question_answer9)
  In the above problem if the lift moves up with an acceleration equal to the acceleration due to gravity, the reading on the spring balance will be    [NCERT 1977]
  A)
                          2 kg                done clear
  B)
                          \[(2\times g)\,kg\]             done clear
  C)
                          \[(4\times g)\,kg\]             done clear
  D)
                            4 kg             done clear
  View Solution play_arrow

• question_answer10)
  A coin is dropped in a lift. It takes time \[{{t}_{1}}\] to reach the floor when lift is stationary. It takes time \[{{t}_{2}}\] when lift is moving up with constant acceleration. Then 
  A)
                          \[{{t}_{1}}>{{t}_{2}}\]             done clear
  B)
                            \[{{t}_{2}}>{{t}_{1}}\]             done clear
  C)
              \[{{t}_{1}}={{t}_{2}}\] done clear
  D)
                            \[{{t}_{1}}>>{{t}_{2}}\] done clear
  View Solution play_arrow

• question_answer11)
  If the tension in the cable of 1000 kg elevator is 1000 kg weight, the elevator                          [NCERT 1971]
  A)
                               Is accelerating upwards             done clear
  B)
                          Is accelerating downwards             done clear
  C)
                          May be at rest or accelerating             done clear
  D)
                        May be at rest or in uniform motion             done clear
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• question_answer12)
  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              [CPMT 1988, 89, 2002]
  A)
                          5 m                  done clear
  B)
                          4.8 m             done clear
  C)
                          3.2 m               done clear
  D)
                          3.0 m done clear
  View Solution play_arrow

• question_answer13)
  In doubling the mass and acceleration of the mass, the force acting on the mass with respect to the previous value
  A)
                          Decreases to half                     done clear
  B)
                          Remains unchanged             done clear
  C)
                          Increases two times                  done clear
  D)
                          Increases four times             done clear
  View Solution play_arrow

• question_answer14)
  A force of 5 N  acts on a body of weight 9.8 N. What is the acceleration produced in \[m/{{\sec }^{2}}\]            [NCERT 1990]
  A)
                          49.00               done clear
  B)
                          5.00             done clear
  C)
                          1.46                 done clear
  D)
                          0.51 done clear
  View Solution play_arrow

• question_answer15)
  A body of mass 40 gm is moving with a constant velocity of 2 cm/sec on a horizontal frictionless table. The force on the table is                          [NCERT 1978]
  A)
                          39200 dyne             done clear
  B)
                            160 dyne             done clear
  C)
                          80 dyne             done clear
  D)
                            Zero dyne done clear
  View Solution play_arrow

• question_answer16)
  When 1 N force acts on 1 kg body that is able to move freely, the body receives                     [CPMT 1971]
  A)
                          A speed of 1 m/sec             done clear
  B)
                          An acceleration of \[1\,m/{{\sec }^{2}}\]           done clear
  C)
                          An acceleration of \[980\,cm/{{\sec }^{2}}\]             done clear
  D)
                          An acceleration of \[1\,cm/{{\sec }^{2}}\] done clear
  View Solution play_arrow

• question_answer17)
  An object with a mass 10 kg moves at a constant velocity of 10 m/sec. A constant force then acts for 4 second on the object and gives it a speed of 2 m/sec in opposite direction. The acceleration produced in it, is                [CPMT 1971]
  A)
                               \[3\,m/{{\sec }^{2}}\]           done clear
  B)
                            \[-3\,m/{{\sec }^{2}}\]           done clear
  C)
                          \[0.3\,m/{{\sec }^{2}}\]             done clear
  D)
                            \[-0.3\,m/{{\sec }^{2}}\] done clear
  View Solution play_arrow

• question_answer18)
  In the above question, the force acting on the object is [CPMT 1971]            
  A)
                               30 N                done clear
  B)
                          ? 30 N             done clear
  C)
                          3 N                  done clear
  D)
                          ? 3 N done clear
  View Solution play_arrow

• question_answer19)
  In the above question, the impulse acting on the object is [CPMT 1971]          
  A)
                               \[120\ newton\times \sec \]                   done clear
  B)
                        \[-120\ newtont\sec \]           done clear
  C)
                          \[30\ newton\times \sec \]                     done clear
  D)
                          \[-30\ newton\times \sec \] done clear
  View Solution play_arrow

• question_answer20)
  A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant the gun fires bullets of mass 10 gm with a velocity of 500 m/sec with respect to the car. The number of bullets fired per second is ten. The average thrust on the system is                   [CPMT 1971]
  A)
                          550 N              done clear
  B)
                          50 N             done clear
  C)
                          250 N              done clear
  D)
                          250 dyne done clear
  View Solution play_arrow

• question_answer21)
  In the above question, the acceleration of the car will be         [CPMT 1971]            
  A)
                               \[0.25\,m/{{\sec }^{2}}\]                done clear
  B)
                          \[2.5\,m/{{\sec }^{2}}\]             done clear
  C)
                          \[5.0\,m/{{\sec }^{2}}\]             done clear
  D)
                          \[0.025\,m/{{\sec }^{2}}\]           done clear
  View Solution play_arrow

• question_answer22)
  A person is standing in an elevator. In which situation he finds his weight less than actual when        [AIIMS 2005]
  A)
                   The elevator moves upward with constant acceleration done clear
  B)
            The elevator moves downward with constant acceleration. done clear
  C)
              The elevator moves upward with uniform velocity done clear
  D)
              The elevator moves downward with uniform velocity done clear
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• question_answer23)
  A particle of mass 0.3 kg is subjected to a force \[F=-kx\] with \[k=15\,N/m.\] What will be its initial acceleration if it is released from a point 20 cm away from the origin [AIEEE 2005]
  A)
              5 m/s2 done clear
  B)
                10 m/s2 done clear
  C)
              3 m/s2 done clear
  D)
              15 m/s2 done clear
  View Solution play_arrow

• question_answer24)
   A block of metal weighing 2 kg is resting on a frictionless plane. It is struck by a jet releasing water at a rate of 1 kg/sec and at a speed of 5 m/sec. The initial acceleration of the block will be                          [MNR 1979]
  A)
                        \[2.5\,m/{{\sec }^{2}}\]           done clear
  B)
                            \[5.0\,m/{{\sec }^{2}}\]             done clear
  C)
                          \[10\,m/{{\sec }^{2}}\]             done clear
  D)
                            None of the above done clear
  View Solution play_arrow

• question_answer25)
  Gravels are dropped on a conveyor belt at the rate of 0.5 kg/sec. The extra force required in newtons to keep the belt moving at 2 m/sec is                                 [EAMCET 1988]
  A)
                          1                      done clear
  B)
                          2             done clear
  C)
                          4                      done clear
  D)
                          0.5 done clear
  View Solution play_arrow

• question_answer26)
  A parachutist of weight ?w? strikes the ground with his legs fixed and comes to rest with an upward acceleration of magnitude 3 g. Force exerted on him by ground during landing is                               [EAMCET 1988]
  A)
                          w                   done clear
  B)
                          2w             done clear
  C)
                          3w                   done clear
  D)
                          4w             done clear
  View Solution play_arrow

• question_answer27)
  At a place where the acceleration due to gravity is \[10\,m\,{{\sec }^{-2}}\] a force of 5 kg-wt acts on a body of mass 10 kg initially at rest. The velocity of the body after 4 second is [EAMCET 1981]          
  A)
                               \[5\,m\,{{\sec }^{-1}}\]             done clear
  B)
                            \[10\,m\,{{\sec }^{-1}}\]             done clear
  C)
                        \[20\,m\,{{\sec }^{-1}}\]           done clear
  D)
                            \[50\,m\,{{\sec }^{-1}}\] done clear
  View Solution play_arrow

• question_answer28)
  In a rocket of mass 1000 kg fuel is consumed at a rate of 40 kg/s. The velocity of the gases ejected from the rocket is \[5\times {{10}^{4}}\,m/s\]. The thrust on the rocket is    [MP PMT 1994]
  A)
                          \[2\times {{10}^{3}}N\]             done clear
  B)
                            \[5\times {{10}^{4}}N\]             done clear
  C)
                          \[2\times {{10}^{6}}N\]           done clear
  D)
                                        \[2\times {{10}^{9}}N\] done clear
  View Solution play_arrow

• question_answer29)
  A man is standing on a weighing machine placed in a lift. When stationary his weight is recorded as 40 kg. If the lift is accelerated upwards with an acceleration of \[2\,m/{{s}^{2}}\], then the weight recorded in the machine will be \[(g=10\,m/{{s}^{2}})\] [MP PMT 1994]            
  A)
                          32 kg                done clear
  B)
                          40 kg             done clear
  C)
                          42 kg                done clear
  D)
                          48 kg             done clear
  View Solution play_arrow

• question_answer30)
  A body of mass 4 kg weighs 4.8 kg when suspended in a moving lift. The acceleration of the lift is     [Manipal MEE 1995]            
  A)
                          \[9.80\,m{{s}^{-2}}\] downwards                done clear
  B)
                          9.80\[m{{s}^{-2}}\] upwards           done clear
  C)
                          1.96\[m{{s}^{-2}}\] downwards                  done clear
  D)
                          1.96\[m{{s}^{-2}}\] upwards             done clear
  View Solution play_arrow

• question_answer31)
  An elevator weighing 6000 kg is pulled upward by a cable with an acceleration of \[5\,m{{s}^{-2}}\]. Taking g to be \[10\,m{{s}^{-2}}\], then the tension in the cable is                [Manipal MEE 1995]
  A)
                          6000 N             done clear
  B)
                            9000 N             done clear
  C)
                          60000 N             done clear
  D)
                            90000 N             done clear
  View Solution play_arrow

• question_answer32)
  A ball of mass 0.2 kg moves with a velocity of 20 m/sec and it stops in  0.1 sec; then the force on the ball is            [BHU 1995]
  A)
                          40 N              done clear
  B)
                          20 N             done clear
  C)
                          4 N                  done clear
  D)
                          2 N done clear
  View Solution play_arrow

• question_answer33)
  A vehicle of 100 kg is moving with a velocity of 5 m/sec. To stop it in \[\frac{1}{10}\sec \], the required force in opposite direction is [MP PET 1995]            
  A)
                               5000 N             done clear
  B)
                          500 N             done clear
  C)
                          50 N                done clear
  D)
                          1000 N done clear
  View Solution play_arrow

• question_answer34)
  A boy having a mass equal to 40 kilograms is standing in an elevator. The force felt by the feet of the boy will begreatest when the elevator             \[(g=9.8\,metres/{{\sec }^{2}})\]     [MP PMT 1995; BVP 2003]            
  A)
                               Stands still             done clear
  B)
                          Moves downward at a constant velocity of 4 metres/sec             done clear
  C)
                          Accelerates downward with an acceleration equal to \[4\,metres/{{\sec }^{2}}\]             done clear
  D)
                          Accelerates upward with an acceleration equal to \[4\,metres/{{\sec }^{2}}\]             done clear
  View Solution play_arrow

• question_answer35)
  A rocket has an initial mass of \[20\times {{10}^{3}}\,kg\]. If it is to blast off with an initial acceleration of \[4\,m{{s}^{-2}}\], the initial thrust needed is \[(g\tilde{=}10\,m{{s}^{-2}})\]    [Kurukshetra CEE 1996]
  A)
                               \[6\times {{10}^{4}}\,N\]                 done clear
  B)
                          \[28\times {{10}^{4}}\,N\]           done clear
  C)
                          \[20\times {{10}^{4}}\,N\]             done clear
  D)
                            \[12\times {{10}^{4}}\,N\] done clear
  View Solution play_arrow

• question_answer36)
  The ratio of the weight of a man in a stationary lift and when it is moving downward with uniform acceleration ?a? is 3 : 2. The value of ?a? is (g-Acceleration due to gravity of the earth)                         [MP PET 1997]
  A)
                          \[\frac{3}{2}g\]                       done clear
  B)
                        \[\frac{g}{3}\]           done clear
  C)
                          \[\frac{2}{3}g\]                     done clear
  D)
                          g done clear
  View Solution play_arrow

• question_answer37)
  The mass of a lift is 500 kg. When it ascends with an acceleration of \[2\,m/{{s}^{2}}\], the tension in the cable will be \[[g=10\,m/{{s}^{2}}]\]                                [MP PMT 1999, 2000]
  A)
                               6000 N             done clear
  B)
                            5000 N             done clear
  C)
                          4000 N             done clear
  D)
                            50 N done clear
  View Solution play_arrow

• question_answer38)
  If force on a rocket having exhaust velocity of 300 m/sec is 210 N, then rate of combustion of the fuel is       [CBSE PMT 1999; MH CET 2003; Pb. PMT 2004]            
  A)
                               0.7 kg/s             done clear
  B)
                                        1.4 kg/s             done clear
  C)
                          0.07 kg/s             done clear
  D)
                            10.7 kg/s done clear
  View Solution play_arrow

• question_answer39)
  In an elevator moving vertically up with an acceleration g, the force exerted on the floor by a passenger of mass M is [CPMT 1999]            
  A)
                               Mg                 done clear
  B)
                          \[\frac{1}{2}Mg\]             done clear
  C)
                          Zero                 done clear
  D)
                          2 Mg             done clear
  View Solution play_arrow

• question_answer40)
  A mass 1 kg is suspended by a thread. It is             (i) lifted up with an acceleration \[4.9\,m/{{s}^{2}}\]             (ii) lowered with an acceleration \[4.9\,m/{{s}^{2}}\].             The ratio of the tensions is                               [CBSE PMT 1998]            
  A)
                          3 : 1               done clear
  B)
                          1 : 3             done clear
  C)
                          1 : 2                 done clear
  D)
                          2 : 1 done clear
  View Solution play_arrow

• question_answer41)
  A 5000 kg rocket is set for vertical firing. The exhaust speed is \[800\,m{{s}^{-1}}\]. To give an initial upward acceleration of \[20\,m{{s}^{-2}}\], the amount of gas ejected per second to supply the needed thrust will be \[(g=10\,m{{s}^{-2}})\]       [CBSE PMT 1998]
  A)
                               \[127.5\,kg\,{{s}^{-1}}\]             done clear
  B)
                            \[187.5\,kg\,{{s}^{-1}}\]           done clear
  C)
                          \[185.5\,kg\,{{s}^{-1}}\]                   done clear
  D)
                          \[137.5\,kg\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer42)
  If a person with a spring balance and a body hanging from it goes up and up in an aeroplane, then the reading of the weight of the body as indicated by the spring balance will [AIIMS 1998; JIPMER 2000]            
  A)
                               Go on increasing                   done clear
  B)
                          Go on decreasing             done clear
  C)
                          First increase and then decrease             done clear
  D)
                          Remain the same done clear
  View Solution play_arrow

• question_answer43)
  The time period of a simple pendulum measured inside a stationary lift is found to be T. If the lift starts accelerating upwards with an acceleration g/3, the time period is [EAMCET 1994; CMEET Bihar 1995; RPMT 2000]            
  A)
                          \[T\sqrt{3}\]                 done clear
  B)
                          \[T\sqrt{3}/2\]           done clear
  C)
                          \[T/\sqrt{3}\]                done clear
  D)
                          \[T/3\] done clear
  View Solution play_arrow

• question_answer44)
  A cork is submerged in water by a spring attached to the bottom of a pail. When the pail is kept in a elevator moving with an acceleration downwards, the spring length [EAMCET (Engg.) 1995]            
  A)
                               Increases             done clear
  B)
                            Decreases             done clear
  C)
                          Remains unchanged                done clear
  D)
                          Data insufficient done clear
  View Solution play_arrow

• question_answer45)
  Two trolleys of mass m and 3m are connected by a spring. They were compressed and released once, they move off in opposite direction and comes to rest after covering distances \[{{S}_{1}}\]and \[{{S}_{2}}\] respectively. Assuming the coefficient of friction to be uniform, the ratio of distances \[{{S}_{1}}:{{S}_{2}}\] is [EAMCET (Engg.) 1995]          
  A)
                               1 : 9                 done clear
  B)
                          1 : 3             done clear
  C)
                          3 : 1                 done clear
  D)
                          9 : 1                 done clear
  View Solution play_arrow

• question_answer46)
  A boy of 50 kg is in a lift moving down with an acceleration \[9.8\,m{{s}^{-2}}\]. The apparent weight of the body is \[(g=9.8\,m{{s}^{-2}})\]     [EAMCET (Med.) 1995; Pb. PMT 1999; KCET 2000]          
  A)
                               \[50\times 9.8\,N\]             done clear
  B)
                            Zero             done clear
  C)
                          50 N                done clear
  D)
                          \[\frac{50}{9.8}N\] done clear
  View Solution play_arrow

• question_answer47)
  A body is imparted motion from rest to move in a straight line. If it is then obstructed by an opposite force, then [NTSE 1995]            
  A)
                               The body may necessarily change direction             done clear
  B)
                          The body is sure to slow down           done clear
  C)
                          The body will necessarily continue to move in the same direction at the same speed             done clear
  D)
                          None of these done clear
  View Solution play_arrow

• question_answer48)
  A mass of 10 gm is suspended by a string and the entire system is falling with a uniform acceleration of \[400\,cm/{{\sec }^{2}}.\]The tension in the string will be \[(g=980\,cm/{{\sec }^{2}})\]                                    [SCRA 1994]
  A)
                               5,800 dyne             done clear
  B)
                            9,800 dyne           done clear
  C)
                          11,800 dyne                 done clear
  D)
                          13,800 dyne done clear
  View Solution play_arrow

• question_answer49)
  A second's pendulum is mounted in a rocket. Its period of oscillation decreases when the rocket        [CBSE PMT 1994]
  A)
                          Comes down with uniform acceleration             done clear
  B)
                          Moves round the earth in a geostationary orbit             done clear
  C)
                          Moves up with a uniform velocity             done clear
  D)
                          Moves up with uniform acceleration           done clear
  View Solution play_arrow

• question_answer50)
  Two balls of masses \[{{m}_{1}}\] and \[{{m}_{2}}\] are separated from each other by a powder charge placed between them. The whole system is at rest on the ground. Suddenly the powder charge explodes and masses are pushed apart. The mass \[{{m}_{1}}\] travels a distance \[{{s}_{1}}\] and stops. If the coefficients of friction between the balls and ground are same, the mass \[{{m}_{2}}\] stops after travelling the distance                           [BHU 1994]
  A)
                          \[{{s}_{2}}=\frac{{{m}_{1}}}{{{m}_{2}}}{{s}_{1}}\]             done clear
  B)
                            \[{{s}_{2}}=\frac{{{m}_{2}}}{{{m}_{1}}}{{s}_{1}}\]             done clear
  C)
                          \[{{s}_{2}}=\frac{m_{1}^{2}}{m_{2}^{2}}{{s}_{1}}\]           done clear
  D)
                            \[{{s}_{2}}=\frac{m_{2}^{2}}{m_{1}^{2}}{{s}_{1}}\] done clear
  View Solution play_arrow

• question_answer51)
  A force vector applied on a mass is represented as \[\vec{F}=6\hat{i}-8\hat{j}+10\hat{k}\] and accelerates with \[1\,m/{{s}^{2}}\]. What will be the mass of the body                                  [CBSE PMT 1996]
  A)
                          \[10\sqrt{2}\,kg\]           done clear
  B)
                            \[2\sqrt{10}\,kg\]             done clear
  C)
                          10 kg                done clear
  D)
                          20 kg done clear
  View Solution play_arrow

• question_answer52)
  A cart of mass M is tied by one end of a massless rope of length 10 m. The other end of the rope is in the hands of a man of mass M. The entire system is on a smooth horizontal surface. The man is at x = 0 and the cart at x = 10 m. If the man pulls the cart by the rope, the man and the cart will meet at the point                            [CBSE PMT 1997]
  A)
                          \[x=0\]             done clear
  B)
                          \[x=5\,m\]           done clear
  C)
                          \[x=10\,m\]                  done clear
  D)
                          They will never meet done clear
  View Solution play_arrow

• question_answer53)
  A cricket ball of mass 250 g collides with a bat with velocity 10 m/s and returns with the same velocity within 0.01 second. The force acted on bat is                    [CPMT 1997]
  A)
                          25 N                done clear
  B)
                          50 N             done clear
  C)
                          250 N              done clear
  D)
                          500 N           done clear
  View Solution play_arrow

• question_answer54)
  A pendulum bob of mass 50 gm is suspended from the ceiling of an elevator. The tension in the string if the elevator goes up with uniform velocity is approximately            [AMU (Med.) 1999]            
  A)
                          0.30 N             done clear
  B)
                          0.40 N           done clear
  C)
                          0.42 N             done clear
  D)
                          0.50 N             done clear
  View Solution play_arrow

• question_answer55)
  A train is moving with velocity 20 m/sec. on this dust is falling at the rate of 50 kg/minute. The extra force required to move this train with constant velocity will be [RPET 1999]
  A)
                        16.66 N           done clear
  B)
                            1000 N           done clear
  C)
                          166.6 N           done clear
  D)
                            1200 N done clear
  View Solution play_arrow

• question_answer56)
  The average force necessary to stop a bullet of mass 20 g moving with a speed of 250 m/s, as it penetrates into the wood for a distance of 12 cm is           [CBSE PMT 2000; DPMT 2003]
  A)
              \[2.2\times {{10}^{3}}N\] done clear
  B)
                \[3.2\times {{10}^{3}}N\] done clear
  C)
              \[4.2\times {{10}^{3}}N\] done clear
  D)
                \[5.2\times {{10}^{3}}N\] done clear
  View Solution play_arrow

• question_answer57)
  The average resisting force that must act on a 5 kg mass to reduce its speed from 65 cm/s to 15 cm/s in 0.2s is [RPET 2000]
  A)
              12.5 N done clear
  B)
                25 N done clear
  C)
              50 N    done clear
  D)
              100 N done clear
  View Solution play_arrow

• question_answer58)
  A mass is hanging on a spring balance which is kept in a lift.  The lift ascends. The spring balance will show in its reading [DCE 2000]
  A)
              Increase done clear
  B)
              Decrease done clear
  C)
              No change done clear
  D)
              Change depending upon velocity done clear
  View Solution play_arrow

• question_answer59)
  An army vehicle of mass 1000 kg is moving with a velocity of 10 m/s and is acted upon by a forward force of 1000  N due to the engine and a retarding force of 500 N due to friction. What will be its velocity after 10 s                        [Pb. PMT 2000]
  A)
              5 m/s   done clear
  B)
              10 m/s done clear
  C)
              15 m/s done clear
  D)
              20 m/s done clear
  View Solution play_arrow

• question_answer60)
  A body of mass 2 kg is moving with a velocity 8 m/s on a smooth surface. If it is to be brought to rest in 4 seconds, then the force to be applied is                          [Pb. PMT 2000]
  A)
              8 N      done clear
  B)
              4 N done clear
  C)
              2 N      done clear
  D)
              1 N done clear
  View Solution play_arrow

• question_answer61)
  The apparent weight of the body, when it is travelling upwards with an acceleration of \[2m/{{s}^{2}}\] and mass is 10 kg, will be                           [Pb. PMT 2001]
  A)
              198 N  done clear
  B)
              164 N done clear
  C)
              140 N  done clear
  D)
              118 N done clear
  View Solution play_arrow

• question_answer62)
  A man measures time period of a pendulum \[(T)\] in stationary lift. If the lift moves upward with acceleration \[\frac{g}{4},\] then new time period will be                           [BHU 2001]
  A)
              \[\frac{2T}{\sqrt{5}}\] done clear
  B)
              \[\frac{\sqrt{5}T}{2}\] done clear
  C)
              \[\frac{\sqrt{5}}{2T}\]            done clear
  D)
              \[\frac{2}{\sqrt{5}T}\] done clear
  View Solution play_arrow

• question_answer63)
  A 30 gm bullet initially travelling at 120 m/s penetrates 12 cm into a wooden block. The average resistance exerted by the wooden block is [AFMC 1999; CPMT 2001]
  A)
              2850N done clear
  B)
              2200 N done clear
  C)
              2000N done clear
  D)
              1800 N done clear
  View Solution play_arrow

• question_answer64)
  A force of 10 Newton acts on a body of mass 20kg for 10 seconds.  Change in its momentum is       [MP PET 2002]
  A)
              5 \[kg\,m/s\] done clear
  B)
                \[100kg\,m/s\] done clear
  C)
              \[200\,kg\,m/s\] done clear
  D)
                1000 \[kg\,m/s\] done clear
  View Solution play_arrow

• question_answer65)
  A body of mass 1.0kg is falling with an acceleration of 10 \[m/se{{c}^{2}}\]. Its apparent weight will be \[(g=10m/{{\sec }^{2}})\] [MP PET 2002]
  A)
              \[1.0\,kg\,wt\] done clear
  B)
                \[2.0\,kg\,wt\] done clear
  C)
              \[0.5\,kg\,wt\] done clear
  D)
                Zero done clear
  View Solution play_arrow

• question_answer66)
  A player caught a cricket ball of mass 150 gm moving at the rate of 20 m/sec. if the catching process be completed in 0.1 sec the force of the blow exerted by the ball on the hands of player is                            [Kerala PET 2005]
  A)
              0.3 N done clear
  B)
                30 N done clear
  C)
              300 N  done clear
  D)
              3000 N done clear
  View Solution play_arrow

• question_answer67)
  If rope of lift breaks suddenly, the tension exerted by the surface of lift                                     [AFMC 2002] (a = acceleration of lift)
  A)
              mg       done clear
  B)
              \[m\,(g+a)\] done clear
  C)
              \[m(g-a)\] done clear
  D)
                \[0\] done clear
  View Solution play_arrow

• question_answer68)
  A boy whose mass is 50kg stands on a spring balance inside a lift. The lift starts to ascent with an acceleration of \[2m{{s}^{-2}}.\] The reading of the machine or balance \[(g=10\,m{{s}^{-2}})\]is [Kerala PET 2002]
  A)
              \[50\,kg\]          done clear
  B)
              Zero done clear
  C)
              \[49\,kg\]          done clear
  D)
              \[60\,kg\] done clear
  View Solution play_arrow

• question_answer69)
  A rocket is ejecting \[50g\] of gases per sec at a speed of \[500\,m/s.\] The accelerating force on the rocket will be [Pb. PMT 2002]
  A)
              \[125\,N\]         done clear
  B)
              \[25\,N\] done clear
  C)
              \[5\,N\] done clear
  D)
              Zero done clear
  View Solution play_arrow

• question_answer70)
  A block of mass \[5\,kg\] is moving horizontally at a speed of 1.5 m/s. A perpendicular force of 5N acts on it for 4 sec. What will be the distance of the block from the point where the force started acting                                 [Pb. PMT 2002]
  A)
              10 m    done clear
  B)
              8 m done clear
  C)
              6 m      done clear
  D)
              2 m done clear
  View Solution play_arrow

• question_answer71)
  A lift of mass 1000 kg is moving with an acceleration of 1 \[m/{{s}^{2}}\] in upward direction. Tension developed in the string, which is connected to the lift, is               [CBSE PMT 2002]
  A)
              9,800 N done clear
  B)
                10,000 N done clear
  C)
              10,800 N done clear
  D)
                11,000 N done clear
  View Solution play_arrow

• question_answer72)
  A lift accelerated downward with acceleration 'a'. A man in the lift throws a ball upward with acceleration \[{{a}_{0}}({{a}_{0}}<a).\] Then acceleration of ball observed by observer, which is on earth, is                                    [AIEEE 2002]
  A)
              \[(a+{{a}_{0}})\] upward done clear
  B)
                \[(a-{{a}_{0}})\] upward done clear
  C)
              \[(a+{{a}_{0}})\] downward            done clear
  D)
              \[(a-{{a}_{0}})\] downward done clear
  View Solution play_arrow

• question_answer73)
  A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively        [AIEEE 2002]
  A)
              \[g,\,g\] done clear
  B)
              \[g-a,\,g-a\] done clear
  C)
              \[g-a,\,g\] done clear
  D)
                \[a,\,g\] done clear
  View Solution play_arrow

• question_answer74)
  A man weighs \[80kg.\] He stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of \[5m/{{s}^{2}}.\] What would be the reading on the scale. \[(g=10m/{{s}^{2}})\]                             [CBSE PMT 2003]
  A)
              400 N  done clear
  B)
              800 N done clear
  C)
              1200 N done clear
  D)
              Zero done clear
  View Solution play_arrow

• question_answer75)
  A monkey of mass 20kg is holding a vertical rope. The rope will not break when a mass of 25 kg is suspended from it but will break if the mass exceeds 25 kg. What is the maximum acceleration with which the monkey can climb up along the rope \[(g=10m/{{s}^{2}})\]                             [CBSE PMT 2003]
  A)
              \[10\,m/{{s}^{2}}\]  done clear
  B)
              \[25\,m/{{s}^{2}}\] done clear
  C)
              \[2.5m/{{s}^{2}}\] done clear
  D)
                \[5m/{{s}^{2}}\] done clear
  View Solution play_arrow

• question_answer76)
  If in a stationary lift, a man is standing with a bucket full of water, having a hole at its bottom. The rate of flow of water through this hole is \[{{R}_{0}}.\] If the lift starts to move up and down with same acceleration and then that rates of flow of water are \[{{R}_{u}}\] and \[{{R}_{d}},\] then                                   [UPSEAT 2003]
  A)
              \[{{R}_{0}}>{{R}_{u}}>{{R}_{d}}\]      done clear
  B)
            \[{{R}_{u}}>{{R}_{0}}>{{R}_{d}}\] done clear
  C)
              \[{{R}_{d}}>{{R}_{0}}>{{R}_{u}}\] done clear
  D)
                \[{{R}_{u}}>{{R}_{d}}>{{R}_{0}}\] done clear
  View Solution play_arrow

• question_answer77)
  A rocket with a lift- off mass \[3.5\times {{10}^{4}}\]\[kg\] is blasted upwards with an initial acceleration of \[10m/{{s}^{2}}.\] Then the initial thrust of the blast is                                [AIEEE 2003]
  A)
              \[1.75\times {{10}^{5}}N\] done clear
  B)
                \[3.5\times {{10}^{5}}N\] done clear
  C)
              \[7.0\times {{10}^{5}}N\] done clear
  D)
                \[14.0\times {{10}^{5}}N\] done clear
  View Solution play_arrow

• question_answer78)
  A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N, when the lift is stationary. If the lift moves downward with an acceleration of \[5\,m/{{s}^{2}},\] the reading of the spring balance will be                                 [AIEEE 2003]
  A)
              49 N    done clear
  B)
              24 N done clear
  C)
              74 N    done clear
  D)
              15 N done clear
  View Solution play_arrow

• question_answer79)
  A plumb line is suspended from a ceiling of a car moving with horizontal acceleration of a. What will be the angle of inclination with vertical                                [Orissa JEE 2003]
  A)
            \[{{\tan }^{-1}}(a/g)\]        done clear
  B)
              \[{{\tan }^{-1}}(g/a)\] done clear
  C)
              \[{{\cos }^{-1}}(a/g)\] done clear
  D)
                \[{{\cos }^{-1}}(g/a)\] done clear
  View Solution play_arrow

• question_answer80)
  Mass of a person sitting in a lift is 50 kg. If lift is coming down with a constant acceleration of 10 \[m/se{{c}^{2}}.\] Then the reading of spring balance will be \[(g=10m/se{{c}^{2}})\]                    [RPET 2003; Kerala PMT 2005]
  A)
              0                      done clear
  B)
              1000N done clear
  C)
                          100 N            done clear
  D)
                          10 N done clear
  View Solution play_arrow

• question_answer81)
  A body of mass 2 kg has an initial velocity of 3 meters per second along OE and it is subjected to a force of 4 N in a direction perpendicular to OE. The distance of the body from O after 4 seconds will be                         [CPMT 1976]
  A)
                          12 m                done clear
  B)
                          20 m             done clear
  C)
                          8 m           done clear
  D)
                            48 m done clear
  View Solution play_arrow

• question_answer82)
  A block of mass m is placed on a smooth wedge of inclination \[\theta \]. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block (g is acceleration due to gravity) will be                               [CBSE PMT 2004]
  A)
              \[mg\cos \theta \] done clear
  B)
                \[mg\sin \theta \] done clear
  C)
                          \[mg\]             done clear
  D)
                          \[mg/\cos \theta \]           done clear
  View Solution play_arrow

• question_answer83)
  A machine gun fires a bullet of mass 40 g with a velocity \[1200\,\,m{{s}^{-1}}.\] The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most                        [AIEEE 2004]
  A)
              One     done clear
  B)
              Four done clear
  C)
              Two     done clear
  D)
              Three done clear
  View Solution play_arrow

• question_answer84)
  An automobile travelling with a speed of \[60\,\,km/h,\] can brake to stop within a distance of 20 m. If the car is going twice as fast, i.e. 120 km/h, the stopping distance will be [AIEEE 2004]
  A)
              20 m    done clear
  B)
              40 m done clear
  C)
              60 m    done clear
  D)
              80 m done clear
  View Solution play_arrow

• question_answer85)
  A man of weight 75 kg is standing in an elevator which is moving with an acceleration of \[5\,m/{{s}^{2}}\] in upward direction the apparent weight of the man will be \[(g=10\,\,m/{{s}^{2}})\] [Pb. PMT 2004]
  A)
              1425 N done clear
  B)
              1375 N done clear
  C)
                          1250 N           done clear
  D)
                          1125 N           done clear
  View Solution play_arrow

• question_answer86)
  The adjacent figure is the part of a horizontally stretched net. section AB is stretched with a force of 10 N. The tensions in the sections BC and BF are                                   [KCET 2005]
  A)
              10 N, 11 N done clear
  B)
                10 N, 6 N done clear
  C)
            10 N, 10 N       done clear
  D)
              Can't calculate due to insufficient data done clear
  View Solution play_arrow

• question_answer87)
  The linear momentum p of a body moving in one dimension varies with time according to the equation \[p=a+b{{t}^{2}}\] where a and b are positive constants. The net force acting on the body is                              [Pb. PET 2002]
  A)
              A constant done clear
  B)
              Proportional to \[{{t}^{2}}\] done clear
  C)
              Inversely proportional to t done clear
  D)
              Proportional to t done clear
  View Solution play_arrow

• question_answer88)
  The spring balance inside a lift suspends an object. As the lift begins to ascent, the reading indicated by the spring balance will                                          [DCE 2003]
  A)
              Increase done clear
  B)
              Decrease done clear
  C)
              Remain unchanged done clear
  D)
              Depend on the speed of ascend done clear
  View Solution play_arrow

• question_answer89)
  There is a simple pendulum hanging from the ceiling of a lift. When the lift is stand still, the time period of the pendulum is T. If the resultant acceleration becomes \[g/4,\] then the new time period of the pendulum is             [DCE 2004]
  A)
              0.8 T    done clear
  B)
              0.25 T done clear
  C)
              2 T       done clear
  D)
              4 T done clear
  View Solution play_arrow

• question_answer90)
  A man of weight 80 kg is standing in an elevator which is moving with an acceleration of \[6\,\,m/{{s}^{2}}\] in upward direction. The apparent weight of the man will be \[(g=10\,m/{{s}^{2}})\]                        [DPMT 2003]
  A)
              1480 N done clear
  B)
              1280 N done clear
  C)
              1380 N done clear
  D)
              None of these done clear
  View Solution play_arrow

• question_answer91)
  A force of 100 dynes acts on a mass of 5 gram for 10 sec. The velocity produced is                           [Pb. PET 2004]
  A)
              \[2000\,\,cm/\sec \] done clear
  B)
                \[200\,\,cm/\sec \] done clear
  C)
              \[20\,\,cm/\sec \] done clear
  D)
                \[2\,\,cm/\sec \] done clear
  View Solution play_arrow

• question_answer92)
  When the speed of a moving body is doubled [UPSEAT 2004]
  A)
              Its acceleration is doubled        done clear
  B)
              Its momentum is doubled         done clear
  C)
              Its kinetic energy is doubled     done clear
  D)
              Its potential energy is doubled done clear
  View Solution play_arrow

• question_answer93)
  A body of mass m collides against a wall with a velocity v and rebounds with the same speed. Its change of momentum is                           [Kerala PMT 2004]
  A)
              2 mv    done clear
  B)
              mv       done clear
  C)
              ? mv    done clear
  D)
              Zero done clear
  View Solution play_arrow

• question_answer94)
  A thief stole a box full of valuable articles of weight W and while carrying it on his back, he jumped down a wall of height ?h? from the ground. Before he reached the ground he experienced a load of                            [NCERT 1973]
  A)
                          2W                   done clear
  B)
                          W             done clear
  C)
                          W/2                  done clear
  D)
                          Zero             done clear
  View Solution play_arrow

• question_answer95)
  N bullets each of mass m kg are fired with a velocity \[v\,m{{s}^{-1}}\] at the rate of n bullets per second upon a wall. The reaction offered by the wall to the bullets is given by
  A)
                          nmv               done clear
  B)
                          \[\frac{Nmv}{n}\]             done clear
  C)
                          \[n\frac{Nm}{v}\]                   done clear
  D)
                          \[n\frac{Nv}{m}\] done clear
  View Solution play_arrow

• question_answer96)
  If a body of mass m is carried by a lift moving with an upward acceleration a, then the forces acting on the body are (i) the reaction R on the floor of the lift upwards (ii) the weight mg of the body acting vertically downwards. The equation of motion will be given by          [MNR 1998]
  A)
                          \[R=mg-ma\]             done clear
  B)
                          \[R=mg+ma\]           done clear
  C)
                          \[R=ma-mg\]             done clear
  D)
                            \[R=mg\times ma\] done clear
  View Solution play_arrow

• question_answer97)
  With what minimum acceleration can a fireman slides down a rope while breaking strength of the rope is \[\frac{2}{3}\] of his weight                            [CPMT 1979]
  A)
                          \[\frac{2}{3}g\]                     done clear
  B)
                          g             done clear
  C)
                          \[\frac{1}{3}g\]                     done clear
  D)
                          Zero done clear
  View Solution play_arrow

• question_answer98)
  A ball of mass m moves with speed v and it strikes normally with a wall and reflected back normally, if its time of contact with wall is t then find force exerted by ball on wall                                       [BCECE 2005]                     
  A)
                          \[\frac{2mv}{t}\]                   done clear
  B)
                          \[\frac{mv}{t}\]             done clear
  C)
                          \[mvt\]              done clear
  D)
                          \[\frac{mv}{2t}\] done clear
  View Solution play_arrow

• question_answer99)
  The velocity of a body at time t = 0 is \[10\sqrt{2}\] m/s in the north-east direction and it is moving with an acceleration of 2 m/s2 directed towards the south.  The magnitude and direction of the velocity of the body after 5 sec will be                                     [AMU (Engg.) 1999]
  A)
              10 m/s, towards east done clear
  B)
              10 m/s, towards north done clear
  C)
              10 m/s, towards south done clear
  D)
              10 m/s, towards north-east done clear
  View Solution play_arrow

• question_answer100)
  A body of mass 5 kg starts from the origin with an initial velocity \[\overrightarrow{u\,}\,=\,30\hat{i}+40\hat{j}\,m{{s}^{-1}}\]. If a constant force \[\overrightarrow{F\,}=-(\hat{i}+5\hat{j})N\] acts on the body, the time in which the y?component of the velocity becomes zero is [EAMCET (Med.) 2000]
  A)
              5 seconds done clear
  B)
                20 seconds done clear
  C)
              40 seconds done clear
  D)
                80 seconds done clear
  View Solution play_arrow

• question_answer101)
  A body of mass 8kg is moved by a force \[F=3x\,N,\] where \[x\] is the distance covered. Initial position is \[x=2\,m\] and the final position is \[x=10\]m. The initial speed is \[0.0m/s.\] The final speed is                                [Orissa JEE 2002]
  A)
              6 m/s   done clear
  B)
              12 m/s done clear
  C)
              18 m/s done clear
  D)
              14 m/s done clear
  View Solution play_arrow

• question_answer102)
  The linear momentum p of a body moving in one dimension varies with time according to the equation \[p=a+b{{t}^{2}}\], where a and b are positive constants. The net force acting on the body is                             [MP PMT 1993]
  A)
              Proportional to \[{{t}^{2}}\] done clear
  B)
              A constant done clear
  C)
              Proportional to t done clear
  D)
              Inversely proportional to t done clear
  View Solution play_arrow

• question_answer103)
  A ball of mass 0.5 kg moving with a velocity of 2 m/sec strikes a wall normally and bounces back with the same speed. If the time of contact between the ball and the wall is one millisecond, the average force exerted by the wall on the ball is                            [CBSE PMT 1990]
  A)
              2000 N done clear
  B)
                1000 N done clear
  C)
              5000 N done clear
  D)
              125 N done clear
  View Solution play_arrow

• question_answer104)
  A particle moves in the xy-plane under the action of a force F such that the components of its linear momentum p at any time t are \[{{p}_{x}}=2\cos t\], \[{{p}_{y}}=2\sin t\]. The angle between F and p  at time t is [MP PET 1996; UPSEAT 2000]
  A)
              \[90{}^\circ \] done clear
  B)
              \[0{}^\circ \] done clear
  C)
              \[180{}^\circ \]          done clear
  D)
              \[30{}^\circ \] done clear
  View Solution play_arrow

• question_answer105)
  n small balls each of mass m impinge elastically each second on a surface with velocity u. The force experienced by the surface will be               [MP PMT/PET 1998; RPET 2001; BHU 2001; MP PMT 2003]
  A)
              mnu     done clear
  B)
              2 mnu done clear
  C)
              4 mnu done clear
  D)
              \[\frac{1}{2}\,mnu\] done clear
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• question_answer106)
  A ball of mass 400 gm is dropped from a height of 5m. A boy on the ground hits the ball vertically upwards with a bat with an average force of 100 newton so that it attains a vertical height of 20 m. The time for which the ball remains in contact with the bat is \[[g=10\,m/{{s}^{2}}]\]  [MP PMT 1999]
  A)
              0.12s    done clear
  B)
              0.08 s done clear
  C)
              0.04 s   done clear
  D)
              12 s done clear
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• question_answer107)
  The time in which a force of 2 N produces a change of momentum of \[0.4\,kg-m{{s}^{-1}}\] in the body is [CMEET Bihar 1995]
  A)
              0.2 s     done clear
  B)
              0.02 s done clear
  C)
              0.5 s     done clear
  D)
              0.05 s done clear
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• question_answer108)
  A gun of mass \[10kg\] fires 4 bullets per second. The mass of each bullet is 20 g and the velocity of the bullet when it leaves the gun is \[300\,m{{s}^{-1}}.\] The force required to hold the gun while firing is [EAMCET (Med.) 2000]
  A)
              6 N done clear
  B)
                8 N done clear
  C)
              24 N    done clear
  D)
              240 N done clear
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• question_answer109)
  A gardner waters the plants by a pipe of diameter 1mm. The water comes out at the rate or 10 cm3/sec. The reactionary force exerted on the hand of the gardner is             [KCET 2000]
  A)
              Zero     done clear
  B)
              \[1.27\times {{10}^{-2}}N\] done clear
  C)
              \[1.27\times {{10}^{-4}}N\] done clear
  D)
              \[0.127N\] done clear
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• question_answer110)
  A solid disc of mass M is just held in air horizontally by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 \[m{{s}^{-1}}\]. If the mass of each stone is \[0.05kg\] what is the mass of the disc\[(g=10m{{s}^{-2}}\])                                     [Kerala (Engg.) 2001]
  A)
              \[1.2kg\]           done clear
  B)
              \[0.5kg\] done clear
  C)
              \[20kg\]            done clear
  D)
              3kg done clear
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• question_answer111)
  A ladder rests against a frictionless vertical wall, with its upper end 6m above the ground and the lower end 4m away from the wall. The weight of the ladder is 500 N and its C. G. at 1/3rd distance from the lower end. Wall's reaction will be, (in Newton)                            [AMU (Med.) 2000]
  A)
              111      done clear
  B)
              333 done clear
  C)
              222      done clear
  D)
              129 done clear
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• question_answer112)
  A satellite in force-free space sweeps stationary interplanetary dust at a rate \[dM/dt=\alpha v\] where M is the mass, v is the velocity of the satellite and \[\alpha \] is a constant. What is the deacceleration of the satellite            [CBSE PMT 1994]
  A)
                          \[-2\alpha {{v}^{2}}/M\]           done clear
  B)
                            \[-\alpha {{v}^{2}}/M\]             done clear
  C)
                          \[+\alpha {{v}^{2}}/M\]           done clear
  D)
                            \[-\alpha {{v}^{2}}\] done clear
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• question_answer113)
  10,000 small balls, each weighing 1 gm, strike one square cm of area per second with a velocity 100 m/s in a normal direction and rebound with the same velocity. The value of pressure on the surface will be                             [MP PMT 1994]
  A)
                          \[2\times {{10}^{3}}\,N/{{m}^{2}}\]                         done clear
  B)
                              \[2\times {{10}^{5}}\,N/{{m}^{2}}\]           done clear
  C)
                          \[{{10}^{7}}\,N/{{m}^{2}}\]                   done clear
  D)
                          \[2\times {{10}^{7}}\,N/{{m}^{2}}\]             done clear
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