STD 11 - Work,energy,power and collision PYQs: JEE Mains Physics – Page 2

Showing 51–100 of 191 questions

51. 51. A \(0.4\,kg\) mass takes \(8 s\) to reach ground when dropped from a certain height ' \(P\) ' above surface of earth. The loss of potential energy in the last second of fall is \(..............J\). [Take \(g =10\,m / s ^2\) ] 2023 Medium
52. 52. A ball of mass \(200\,g\) rests on a vertical post of height \(20\,m\). A bullet of mass \(10\,g\), travelling in horizontal direction, hits the centre of the ball. After collision both travels independently. The ball hits the ground at a distance \(30\,m\) and the bullet at a distance of \(120\,m\) from the foot of the post. The value of initial velocity of the bullet will be \(............m/s\) (if \(\left.g =10 m / s ^2\right)\) 2023 Hard
53. 53. A block is fastened to a horizontal spring. The block is pulled to a distance \(x =10\,cm\) from its equilibrium position (at \(x =0\) ) on a frictionless surface from rest. The energy of the block at \(x =5\) \(cm\) is \(0.25\,J\). The spring constant of the spring is \(.........Nm ^{-1}\) 2023 Medium
54. 54. A block of mass \(10\,kg\) is moving along \(x\)-axis under the action of force \(F=5 x\; N\). The work done by the force in moving the block from \(x =2\,m\) to \(4\,m\) will be ............\(J\). 2023 Medium
55. 55. A block of mass \(5\,kg\) starting from rest pulled up on a smooth incline plane making an angle of \(30^{\circ}\) with horizontal with an affective acceleration of \(1\,ms ^{-2}\). The 10.Power delivered by the pulling force at \(t =10\,s\) from the start is \(.....\,W.\) \(\left[\right.\) Use \(\left.g =10\,ms ^{-2}\right]\) (calculate the nearest integer value)   2023 Hard
56. 56. A body is dropped on ground from a height \(h_1\) and after hitting the ground, it rebounds to a height \(h _2\) If the ratio of velocities of the body just before and after hitting ground is \(4\), then percentage loss in kinetic energy of the body is \(\frac{x}{4}\). The value of \(x\) is \(.......\) 2023 Hard
57. 57. A body of mass \(1 kg\) begins to move under the action of a time dependent force \(\vec{F}=\left(t \hat{i}+3 t^2 \hat{ j }\right) N\). where \(\hat{i}\) and \(\hat{j}\) are the unit vectors along \(x\) and \(y\) axis. The 10.Power developed by above force, at the time \(t=2 s\). will be \(..............W\). 2023 Medium
58. 58. A body of mass \(1\,kg\) collides head on elastically with a stationary body of mass \(3\,kg\). After collision, the smaller body reverses its direction of motion and moves with a speed of \(2\,m / s\). The initial speed of the smaller body before collision is \(..........ms ^{-1}\) 2023 Medium
59. 59. A body of mass \(2\,kg\) is initially at rest. It starts moving unidirectionally under the influence of a source of constant 10.Power P. Its displacement in \(4\,s\) is \(\frac{1}{3} \alpha^2 \sqrt{ P } m\). The value of \(\alpha\) will be \(.............\) 2023 Medium
60. 60. A body of mass \(5\,kg\) is moving with a momentum of \(10\,kg\,ms ^{-1}\). Now a force of \(2\,N\) acts on the body in the direction of its motion for \(5\,s\). The increase in the Kinetic energy of the body is \(...........J\). 2023 Medium
61. 61. A car accelerates from rest to \(u\,m / s\). The energy spent in this process is \(E\,J\). The energy required to accelerate the car from \(u\,m / s\) to \(2u\,m / s\) is \(nE\,J\). The value of \(n\) is .............. 2023 Medium
62. 62. A closed circular tube of average radius \(15\,cm\), whose inner walls are rough, is kept in vertical plane. A block of mass \(1\,kg\) just fit inside the tube. The speed of block is \(22\,m / s\), when it is introduced at the top of tube. After completing five oscillations, the block stops at the bottom region of tube. The work done by the tube on the block is \(......J\). [Given \(g=10\,m / s ^2\) ]
    2023 Hard
63. 63. A force \(\overrightarrow{ F }=(2+3 x) \hat{ i }\) acts on a particle in the \(x\) direction where \(F\) is in newton and \(x\) is in meter. The work done by this force during a displacement from \(x =0\) to \(x =4\,m\), is .......\(J\). 2023 Medium
64. 64. A force \(F=\left(5+3 y^2\right)\) acts on a particle in the \(y\) direction, where \(F\) is newton and \(y\) is in meter. The work done by the force during a displacement from \(y =2\,m\) to \(y =5\,m\) is \(.............\,j\). 2023 Medium
65. 65. A lift of mass \(M =500\,kg\) is descending with speed of \(2\,ms ^{-1}\). Its supporting cable begins to slip thus allowing it to fall with a constant acceleration of \(2\,ms ^{-2}\). The kinetic energy of the lift at the end of fall through to a distance of \(6 m\) will be \(...........kJ.\) 2023 Medium
66. 66. A particle of mass \(10\,g\) moves in a straight line with retarcation \(2x\), where \(x\) is the displacement in \(SI\) units. Its loss of kinetic energy for above displacement is \(\left(\frac{10}{x}\right)^{- n }\, J\). The value of \(n\) will be \(............\). 2023 Hard
67. 67. A particle of mass \(m\) moving with velocity \(v\) collides with a stationary particle of mass \(2m\). After collision, they stick together and continue to move together with velocity ........ 2023 Medium
68. 68. A small particle moves to position \(5 \hat{i}-2 \hat{j}+\hat{k}\) from its initial position \(2 \hat{i}+3 \hat{j}-4 \hat{k}\) under the action of force \(5 \hat{i}+2 \hat{j}+7 \hat{k} N\). The value of work done will be \(............J\). 2023 Easy
69. 69. A spherical body of mass \(2\,kg\) starting from rest acquires a kinetic energy of \(10000\,J\) at the end of \(5^{\text {th }}\) second. The force acted on the body is \(.....N\) 2023 Medium
70. 70. An object of mass ' \(m\) ' initially at rest on a smooth horizontal plane starts moving under the action of force \(F=2 N\). In the process of its linear motion, the angle \(\theta\) (as shown in figure) between the direction of force and horizontal varies as \(\theta= kx\), where \(k\) is a constant and \(x\) is the distance covered by the object from its initial position. The expression of kinetic energy of the object will be \(E =\frac{ n }{ k } \sin \theta\). The value of \(n\) is \(.....\)
    2023 Hard
71. 71. As per the given figure, a small ball \(P\) slides down the quadrant of a circle and hits the other ball \(Q\) of equal mass which is initially at rest. Neglecting the effect of friction and assume the collision to be elastic, the velocity of ball \(Q\) after collision will be \(............\,m/s\) \(:\left( g =10\,m / s ^2\right)\)
    2023 Medium
72. 72. For a body projected at an angle with the horizontal from the ground, choose the correct statement. 2023 Medium
73. 73. Given below are two statements: Statement \(I:\) A truck and a car moving with same kinetic energy are brought to rest by applying brakes which provide equal retarding forces. Both come to rest in equal distance. Statement \(II:\) A car moving towards east takes a turn and moves towards north, the speed remains unchanged. The acceleration of the car is zero. In the light of given statements, choose the most appropriate answer from the options given below. 2023 Medium
74. 74. If the maximum load carried by an elevator is \(1400\,kg\) (\(600\,kg\) - Passenger \(+800\,kg\) - elevator), which is moving up with a uniform speed of \(3\,ms ^{-1}\) and the frictional force acting on it is \(2000\,N\), then the maximum 10.Power used by the motor is \(...........\,kW \left( g =10\,m / s ^2\right)\). 2023 Medium
75. 75. The momentum of a body is increased by \(50 \%\). The percentage increase in the kinetic energy of the body is \(...........\,\%\) 2023 Medium
76. 76. The ratio of 10.Powers of two motors is \(\frac{3 \sqrt{x}}{\sqrt{x}+1}\), that are capable of raising \(300\,kg\) water in \(5\) minutes and \(50\,kg\) water in \(2\) minutes respectively from a well of \(100\,m\) deep. The value of \(x\) will be 2023 Medium
77. 77. To maintain a speed of \(80\,km / h\) by a bus of mass \(500\,kg\) on a plane rough road for \(4\,km\) distance, the work done by the engine of the bus will be \(........\,kJ\). [The coefficient of friction between tyre of bus and road is \(0.04]\). 2023 Medium
78. 78. Two bodies are having kinetic energies in the ratio \(16: 9\). If they have same linear momentum, the ratio of their masses respectively is 2023 Easy
79. 79. A \(0.5 \,kg\) block moving at a speed of \(12 \,ms ^{-1}\) compresses a spring through a distance \(30\, cm\) when its speed is halved. The spring constant of the spring will be \(Nm ^{-1}\). 2022 Medium
80. 80. A bag of sand of mass \(9.8\,kg\) is suspended by a rope. A bullet of \(200 \,g\) travelling with speed \(10\, ms ^{-1}\) gets embedded in it, then loss of kinetic energy will be \(...J\) 2022 Medium
81. 81. A ball of mass \(100 \,g\) is dropped from a height \(h =\) \(10\, cm\) on a platform fixed at the top of vertical spring (as shown in figure). The ball stays on the platform and the platform is depressed by a distance \(\frac{ h }{2}\). The spring constant is.......... \(Nm^{-1}\) . (Use \(g=10\, ms ^{-2}\) )
    2022 Medium
82. 82. A block of mass ' \(m\) ' (as shown in figure) moving with kinetic energy \(E\) compresses a spring through a distance \(25\,cm\) when, its speed is halved. The value of spring constant of used spring will be \(nE\; Nm ^{-1}\) for \(n=\)
    2022 Hard
83. 83. A body of mass \(0.5\, kg\) travels on straight line path with velocity \(v =\left(3 x ^{2}+4\right) m / s\). The net workdone by the force during its displacement from \(x =0\) to \(x =2\, m\) is\(.......J\) 2022 Medium
84. 84. A body of mass \(8\,kg\) and another of mass \(2\, kg\) are moving with equal kinetic energy. The ratio of their respective momenta will be. 2022 Easy
85. 85. A bullet of mass \(200\,g\) having initial kinetic energy \(90\,J\) is shot inside a long swimming pool as shown in the figure. If it's kinetic energy reduces to \(40\,J\) within 1s, the minimum length of the pool, the bullet has a to travel so that it completely comes to rest is \(.....m\)
    2022 Hard
86. 86. A particle experiences a variable force \(\overrightarrow{ F }=\left(4 x \hat{ i }+3 y ^{2} \hat{ j }\right)\) in a horizontal \(x - y\) plane. Assume distance in meters and force is newton. If the particle moves from point \((1,2)\) to point \((2,3)\) in the \(x-y\) plane, the Kinetic Energy changes by............\(j\) 2022 Medium
87. 87. A particle of mass \(500 \,gm\) is moving in a straight line with velocity \(v=b x^{5 / 2}\). The work done by the net force during its displacement from \(x=0\) to \(x =4 \,m\) is ...................\(J\) (Take \(b =0.25 \,m ^{-3 / 2} s ^{-1}\) ) 2022 Medium
88. 88. A particle of mass \(m\) is moving in a circular path of constant radius \(I\) such that its centripetal acceleration \((a)\) is varying with time \(t\) as \(a=k^{2} rt^{2}\). where \(k\) is a constant. The 10.Power delivered to the particle by the force acting on it is given as 2022 Hard
89. 89. A pendulum of length \(2 \; m\) consists of a wooden bob of mass \(50 \; g\). A bullet of mass \(75 \; g\) is fired towards the stationary bob with a speed \(v\). The bullet emerges out of the bob with a speed \(\frac{v}{3}\) and the bob just completes the vertical circle. The value of \(v\) is \(\dots \; ms ^{-1}\). (if \(g =10 \; m / s ^{2}\) ) 2022 Hard
90. 90. A stone tide to a string of length \(L\) is whirled in a vertical circle with the other end of the string at the centre. At a certain instant of time, the stone is at its lowest position and has a speed \(u\). The magnitude of change in its velocity, as it reaches a position where the string is horizontal, is \(\sqrt{ x \left( u ^{2}- gL \right)}\). The value of \(x\) is ............. 2022 Medium
91. 91. Arrange the four graphs in descending order of total work done; where \(W _{1}, W _{2}, W _{3}\) and \(W _{4}\) are the work done corresponding to figure \(a , b , c\) and d respectively.
    2022 Medium
92. 92. As per the given figure, two blocks each of mass \(250\,g\) are connected to a spring of spring constant \(2\,Nm ^{-1}\). If both are given velocity \(V\) in opposite directions, then maximum elongation of the spring is:
    2022 Hard
93. 93. If momentum of a body is increased by \(20 \%\), then its kinetic energy increases by\(....\%\) 2022 Medium
94. 94. In the given figure, the block of mass \(m\) is dropped from the point ' \(A\) '. The expression for kinetic energy of block when it reaches point ' \(B\) ' is ................
    2022 Medium
95. 95. Potential energy as a function of \(r\) is given by \(U=\frac{ A }{ r ^{10}}-\frac{ B }{ r ^{5}}\), where \(r\) is the interatomic distance, \(A \) and \(B\) are positive constants. The equilibrium distance between the two atoms will be 2022 Medium
96. 96. Sand is being dropped from a stationary dropper at a rate of \(0.5\,kgs ^{-1}\) on a conveyor belt moving with a velocity of \(5\,ms ^{-1}\). The 10.Power needed to keep belt moving with the same velocity will be. 2022 Medium
97. 97. Two inclined planes are placed as shown in figure. A block is projected from the Point \(A\) of inclined plane \(A B\) along its surface with a velocity just sufficient to carry it to the top Point \(B\) at a height \(10 m\). After reaching the Point \(B\) the block slides down on inclined plane \(BC\). Time it takes to reach to the point \(C\) from point \(A\) is \(t (\sqrt{2}+1) s\). The value of \(t\) is........(use \(g =10 m / s ^{2}\) )
    2022 Hard
98. 98. What percentage of kinetic energy of a moving particle is transferred to a stationary particle when it strikes the stationary particle of \(5\) times its mass? (Assume the collision to be head-on elastic collision) 2022 Hard
99. 99. A ball of mass \(10\, kg\) moving with a velocity \(10 \sqrt{3}\, ms ^{-1}\) along \(X-\)axis, hits another ball of mass \(20\, kg\) which is at rest. After collision, the first ball comes to rest and the second one disintegrates into two equal pieces. One of the pieces starts moving along \(Y-\) axis at a speed of \(10\, m / s\). The second piece starts moving at a speed of \(20\, m / s\) at an angle \(\theta\) (degree) with respect to the \(X-\)axis. The configuration of pieces after collision is shown in the figure. The value of \(\theta\) to the nearest integer is
    2021 Hard
100. 100. A ball of mass \(10\, kg\) moving with a velocity \(10 \sqrt{3} m / s\) along the \(x-\)axis, hits another ball of mass \(20\, kg\) which is at rest. After the collision, first ball comes to rest while the second ball disintegrates into two equal pieces. One piece starts moving along \(y-\)axis with a speed of \(10\) \(m / s\). The second piece starts moving at an angle of \(30^{\circ}\) with respect to the \(x-\)axis. The velocity of the ball moving at \(30^{\circ}\) with \(x-\) axis is \(x\, m / s\). The configuration of pieces after collision is shown in the figure below. The value of \(x\) to the nearest integer is
     2021 Hard

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