JEE Main & Advanced Physics Motion in a Straight Line / सरल रेखा में गति Question Bank

done Mock Test - Motion in one Dimension Total Questions - 25

• question_answer1)
  A particle moving in a straight line covers half the distance with speed of 3 m/s. The other half of the distance is covered in two equal time intervals with speed of 4.5 m/s and 7.5 m/s respectively. The average speed of the particle during this motion is
  A)
  4.0 m/s  done clear
  B)
  5.0 m/s done clear
  C)
  5.5 m/s  done clear
  D)
  4.8 m/s done clear
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• question_answer2)
  A frictionless wire AB is fixed on a sphere of radius R. A very small spherical ball slips on this wire. The time taken by this ball to slip from A to B is
  A)
  \[\frac{2\sqrt{gR}}{g\cos \theta }\]           done clear
  B)
  \[2\sqrt[{}]{gR,}\]\[\frac{\cos \theta }{2}\] done clear
  C)
  \[\sqrt[2]{\frac{R}{g}}\]              done clear
  D)
  \[\frac{gR}{\sqrt{g\cos \theta }}\] done clear
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• question_answer3)
  A body is slipping from an inclined plane of height h and length \[l\]. If the angle of inclination is \[\theta \], the time taken by the body to come from the top to the bottom of this inclined plane is
  A)
  \[\sqrt{\frac{2h}{g}}\]    done clear
  B)
  \[\sqrt{\frac{2l}{g}}\] done clear
  C)
  \[\frac{1}{\sin \theta }\sqrt{\frac{2h}{g}}\]           done clear
  D)
  \[\sin \theta \sqrt{\frac{2h}{g}}\] done clear
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• question_answer4)
  A particle moves with uniform acceleration along a straight line AB. Its velocities at A and B are 2 m/s and 14 m/s, respectively. M is the mid-point of AB. The particle takes \[{{t}_{1}}\] seconds to go from A to M and \[{{t}_{2}}\] seconds to go from M to B. Then  \[{{t}_{2}}/{{t}_{1}}\] is
  A)
  1 : 1                  done clear
  B)
  2 : 1 done clear
  C)
  1:2                    done clear
  D)
  3:1 done clear
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• question_answer5)
  A police party is chasing a dacoit in a jeep which is moving at a constant speed v. The dacoit is on a motorcycle. When he is at a distance x from the jeep, he accelerates from rest at a constant rate. Which of the following relations is true if the police is able to catch the dacoit?
  A)
  \[{{v}^{2}}\le \alpha x\]           done clear
  B)
  \[{{v}^{2}}\le 2\alpha x\] done clear
  C)
  \[{{v}^{2}}\ge 2\alpha x\]         done clear
  D)
  \[{{v}^{2}}\ge \alpha x\] done clear
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• question_answer6)
  A train is moving at a constant speed V when its driver observes another train in front of him on the same track and moving in the same direction with constant speed v. If the distance between the trains is x, then what should be the minimum retardation of the train so as to avoid collision?
  A)
  \[\frac{(V+v)_{{}}^{2}}{x}\]   done clear
  B)
  \[\frac{(V-v)_{{}}^{2}}{x}\] done clear
  C)
  \[\frac{(V+v)_{{}}^{2}}{2x}\] done clear
  D)
  \[\frac{(V-v)_{{}}^{2}}{2x}\] done clear
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• question_answer7)
  A bird flies to and fro between two cars which move with velocities \[{{v}_{1}}\] = 20 m/s and \[{{v}_{2}}\] = 30 m/s. If the speed of the bird is \[{{v}_{3}}\] = 10 m/s and the initial distance of separation between them is d= 2 km, find the total distance covered by the bird till the cars meet.
  A)
  2000 m done clear
  B)
  1000 m done clear
  C)
  400 m   done clear
  D)
  200 m done clear
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• question_answer8)
  A man swimming downstream overcome a float at a point M After travelling distance D he turned back and passed the float at a distance of D/2 from the point M, then the ratio of speed of swimmer with respect to still water to the speed of the river will be
  A)
  2                      done clear
  B)
  3 done clear
  C)
  4                      done clear
  D)
  2.5 done clear
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• question_answer9)
  Two balls are dropped from the top of a high tower with a time interval of \[{{t}_{0}}\] second, where \[{{t}_{0}}\] is smaller than the time taken by the first ball to reach the floor, which is perfectly inelastic. The distance S between the two balls, plotted against the time lapse \[{{t}_{{}}}\]from the instant of dropping the second ball, is best represented by
  A)
            done clear
  B)
  done clear
  C)
           done clear
  D)
  done clear
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• question_answer10)
  A particle is thrown up inside a stationary lift of sufficient height. The time of flight is T. Now it is thrown again with same initial speed\[{{v}_{0}}\]with respect to lift. At the time of second throw, lift is moving up with speed \[{{v}_{0}}\] and uniform acceleration g upward (the acceleration due to gravity). The new time of flight is
  A)
  \[\sqrt{2T}\]       done clear
  B)
  \[\frac{T}{2}\] done clear
  C)
  \[T\]                  done clear
  D)
  \[2T\] done clear
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• question_answer11)
  An insect moving along a straight line, travels in every second distance equal to the magnitude of time elapsed. Assuming acceleration to be constant, and the insect starts at \[t=0\]. Find the magnitude of initial velocity of insect
  A)
  \[\frac{3}{2}unit\]          done clear
  B)
  \[\frac{5}{4}unit\] done clear
  C)
  \[2\,unit\]           done clear
  D)
  \[\frac{1}{2}unit\] done clear
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• question_answer12)
  Two bikes A and B start from a point. A moves with uniform speed 40 m/s and B starts from rest with uniform acceleration \[2\,m/{{s}^{2}}\]. If B starts at \[t=10\] and A starts from the same point at \[t=10\] s, then the time during the journey in which A was ahead of B is
  A)
  20 s                  done clear
  B)
  8 s done clear
  C)
  10 s                  done clear
  D)
  A is never ahead of B done clear
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• question_answer13)
  Three forces start acting simultaneously on a particle moving with velocity \[{{v}^{\to }}\]. These forces are represented in magnitude and direction by the three sides of a triangle ABC (as shown). The particle will now move with velocity
  A)
  \[\overrightarrow{v}\]remaining unchanged done clear
  B)
  less than \[\overrightarrow{v}\]                        done clear
  C)
  greater than \[\overrightarrow{v}\] done clear
  D)
  \[\left| \overrightarrow{v} \right|\] in the direction of the largest force BC done clear
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• question_answer14)
  A body starts from rest with uniform acceleration. If its velocity after n second is v, then its displacement in the last two seconds is
  A)
  \[\frac{2v(n+1)}{n}\]                 done clear
  B)
  \[\frac{v(n+1)}{n}\] done clear
  C)
  \[\frac{v(n-1)}{n}\]                     done clear
  D)
  \[\frac{2v(n-1)}{n}\] done clear
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• question_answer15)
  A particle is moving in a straight line and passes through a point \[O\] with a velocity of 6 \[m{{s}^{-1}}\] .The particle moves with a constant retardation of 2 \[m{{s}^{-2}}\] for 4 s and there after moves with constant velocity. How long after leaving \[O\] does the particle return to \[o\]?
  A)
  3 s                    done clear
  B)
  8 s done clear
  C)
  Never    done clear
  D)
  4 s done clear
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• question_answer16)
  A projectile is fired vertically upwards with an initial velocity \[u\]. After an interval of T seconds, a second projectile is fired vertically upwards, also with initial velocity \[u\].
  A)
  They meet at time \[t=\frac{u}{g}\] and at a height \[\frac{{{u}^{2}}}{2g}+\frac{g{{T}^{2}}}{8}\] done clear
  B)
  They meet at time\[t=\frac{u}{g}+\frac{T}{2}\] and at a height \[\frac{{{u}^{2}}}{2g}+\frac{g{{T}^{2}}}{8}\] done clear
  C)
   They meet at time \[t=\frac{u}{g}+\frac{T}{2}\] and at a height \[\frac{{{u}^{2}}}{2g}-\frac{g{{T}^{2}}}{8}\] done clear
  D)
   They never meet done clear
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• question_answer17)
  A ball is dropped vertically from a height \[d\] above the ground. It hits the ground and bounces up vertically to a height \[d/2\]. Neglecting subsequent motion and air resistance, its velocity v varies with the height h above the ground is correctly shown in
  A)
  done clear
  B)
  done clear
  C)
     done clear
  D)
    done clear
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• question_answer18)
  Two trains, which are moving along different tracks in opposite directions, are put on the same track due to a mistake. Their drivers, on noticing the mistake, start slowing down the trains when the trains are 300 m apart. Graphs given below show their velocities as function of time as the trains slow down. The separation between the trains when both have stopped is
  A)
  120 m   done clear
  B)
  280 m done clear
  C)
  60 m                 done clear
  D)
  20 m done clear
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• question_answer19)
  A drunkard is walking along a straight road. He takes five steps forward and three steps backward and so on. Each step is 1 m long and takes 1 s. There is a pit on the road 11 m away from the starting point. The drunkard will fall into the pit after
  A)
  29 s                  done clear
  B)
  21 s done clear
  C)
  37 s                  done clear
  D)
  31 s done clear
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• question_answer20)
  A ball is thrown from the top of a tower in vertically upward direction. The velocity at a point \[h\]meter below the point of projection is twice of the velocity at a point h meter above the point of projection. Find the maximum height reached by the ball above the top of tower.
  A)
  \[2h\]                 done clear
  B)
  \[3h\] done clear
  C)
  \[(5/3)h\]            done clear
  D)
  \[(4/3)h\] done clear
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• question_answer21)
  A stone is dropped from the top of a tower of height \[h\]. After 1 s another stone is dropped from the balcony 20 m below the top. Both reach the bottom simultaneously. What is the value of \[h\] in (m)? Take \[g=10\,m{{s}^{-2}}\].
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• question_answer22)
  Imagine yourself standing in an elevator which is moving with an upward acceleration \[a=2\,m/{{s}^{2}}\]. A coin is dropped from rest from the roof of the elevator, relative to you. The roof to floor height of the elevator is 1.5 m. (Take \[g=10\,m/{{s}^{2}}\].) Find the velocity in (m/s) of the coin relative to you when it strikes the base of the elevator.
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• question_answer23)
  A parachutist drops first freely from an aeroplane for 10 sand then his parachute opens out. Now he descends with a net retardation of 2.5\[m{{s}^{-2}}\]. If he bails out of the plane at a height of 2495 m and \[g=10\,m{{s}^{-2}}\], his velocity on reaching the ground will be \[m{{s}^{-1}}\].
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• question_answer24)
  The displacement x of a particle moving in one dimension under the action of a constant force is related to time \[t\] by the equation \[t=\sqrt{x}+3\], where x is in meters and \[t\] is in seconds. Find the displacement of the particle when its velocity is zero.
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• question_answer25)
  A parachutist after bailing out falls 50 m without friction. When his parachute opens, it decelerates at \[2\,m/{{s}^{2}}\]. He reaches the ground with .a speed of 3 m/s. At what height in (m) did he bail out?
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