Work, Energy and Power — practice questions

104 curated practice questions from Work, Energy and Power (Physics JEE Main, NTA Exams) — 9 hard, 85 easy, 10 medium. Every question includes the final answer free; step-by-step worked solutions with a free account.

• A force F =-k( y +x j ) (where k is a positive constant) acts on a particle moving in the X-Y plane. Starting from the…
• The P.E. and KE of a helicopter flying horizontally at a height 400 m are in the ratio 5 : 2. The velocity of…
• The KE of a 500 gram stone is 100 J. Against a force of 50 N, how long will it travel?
• A truck weighing 1000 kg changes its speed from 36 km/h to 72 km/h in 2 minutes. Thus, the work done by the engine on…
• Given below are two statements. STATEMENT - 1: Forces acting along the line joining the centers of two bodies are known…
• The potential energy of a particle varies with distance x as shown in the graph. The force acting on the particle is…
• A pump of 200 W power is lifting 2 kg water from an average depth of 10 m per second. Velocity of water delivered by…
• A ball of mass 5 kg experiences a force F = 2 x 2 + x. Work done in displacing the ball by 2 m from origin is:
• The heart of a man pumps 5 litres of blood through the arteries per minute at a pressure of 150 mm of mercury. If the…
• A body of mass 500 g is taken up an inclined plane of length 10 m and height 5 m, and then released to slide down to…
• The work done by a force F = (-6 x^ 3 i ) N is displacing a particle from x = 4 m to x = –2 m is
• A spring of force constant 800 N/m has an extension of 5 cm. The work done in extending it from 5 cm to 15 cm is
• The diagrams represent the potential energy (U) of a function of the inter-atomic distance r. Which diagram corresponds…
• The power of a water pump is 2 kW. If g = 10 m/s 2 , the amount of water it can raise in one minute to a height of 10 m…
• A box is dragged across a floor by a rope which makes an angle of 45° with the horizontal. The tension in the rope is…
• A body of mass 8 kg is moved by a force F=3 x newton, where x is the distance covered. Initial position is x = 2 m and…
• A block of mass 0.5 kg has an initial velocity of 10 m/s. down an inclined plane of angle 30°, the coefficient of…
• An elastic string of unstretched length L and force constant k is stretched by a small length x. It is further…
• What average force is necessary to stop a bullet of mass 20 gm and speed 250 m/sec as it penetrates wood to a distance…
• The displacement of a body of mass 2 kg varies with time t as s = t2 + 2t, where s is in meters and t is in seconds…
• A particle is released from the top of two inclined rough surfaces of height ‘h’ each. The angle of inclination of the…
• The momentum of a body is numerically equal to its kinetic energy. The velocity of the body is
• A long spring, when stretched by a distance x, has potential energy U. On increasing the stretching to nx, the…
• A man is riding on a cycle with velocity 7.2 km/hr up a hill having a slope 1 in 20. Total mass of the man and cycle is…
• An object moving horizontally with kinetic energy of 800 J experiences a constant opposing force of 100 N while moving…
• A particle is released from a height H. At certain height its kinetic energy is two times its potential energy. Height…
• On changing the length of a spring by 0.1 m there is a change of 5 J in its potential energy. The force constant of the…
• A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically…
• Three particles A, B and C are projected from the top of a tower with the same speed. A is thrown straight upwards B…
• A man has a box of weight 10 kg. The energy of the box, when the man runs with a constant velocity of 2 m/sec along…
• An object of mass m is allowed to fall from rest along a rough inclined plane. The speed of the object on reaching the…
• The relationship between force and position is shown in figure (in one dimensional case). The work done by the force in…
• Given below are two statements. STATEMENT - 1: A force is conservative, if the work done on a particle that moves…
• A 120 g mass has a velocity v =(2 i +5 j ) m s^ -1 at a certain instant. K.E. of the body at that instant is
• A body is falling with velocity 1 m/s at a height 3 m from the ground. The speed at height 2 m from the ground will be:
• A particle of mass 0.5 kg is displaced from position r _ 1 (2, 3, 1) to r _ 2 (4, 3, 2) by applying a force of…
• A block is moved from rest through a distance of 4 m along a straight-line path. The mass of the block is 5 kg and the…
• A car covers a distance of 10 km along an inclined plane under the action of a horizontal force of 5 N. The work done…
• The net work done by the tension in the figure when the bigger block of mass M touches the ground is:
• A ball is dropped from a height h on a floor of coefficient of restitution e. The total distance covered by the ball…
• A particle is moving in a conservative force field from point A to point B. U A and U B are the potential energies of…
• A particle is moved from (0, 0) to (a, a) under a force F =( 3 i +4 j ) from two paths. Path 1 is OP and path 2 is OQP…
• A pendulum of length 2 m left at A. When it reaches B, it loses 10% of its total energy due to air resistance. The…
• The work done in time t on a body of mass m which is accelerated from rest to a speed v in time t1 as a function of…
• A body of mass m was slowly pulled up the hill by a force F which at each point was directed along the tangent to the…
• A man weighing 60 kg lifts a body of mass 15 kg to the top of a building 10 m high in 3 minutes. His efficiency is
• The potential energy function for the force between the two atoms in a diatomic molecule is approximately given by…
• A 75 kW engine is generating full power. It is able to provide a 800 kg aeroplane a speed of 2.5 m/s. Find the fraction…
• A particle of mass 0.l kg is subjected to a force which varies with distance as shown in figure. If it starts its…
• A rod of mass m and length l is lying on a horizontal table. Work done in making it stand on one end will be:
• The work done by a particle moving with a velocity of 0.7 c (where c is the velocity of light) in empty space free of…
• Work done by the conservative forces on a system is equal to
• If water falls from a dam into a turbine wheel 19.6 m below, then velocity of water at turbine, is (Take g = 9.8 m/s 2 )
• Given below are two statements Statement I : The work done in moving a body over a closed loop is zero for every force…
• Given below are two statements. One is labelled as Assertion and the other is labelled as Reason. Assertion: Tungsten…
• A particle at rest on a frictionless table is acted upon by a horizontal force which is constant in magnitude and…
• Atomic power station at Tarapur has a generating capacity of 200 MW. The energy generated in a day at this station is
• Given below are two statements. STATEMENT - 1: A cubical block is lifted from the floor and placed on a table. In this…
• A 40 kg skater traveling at 4 m/s overtakes a 60 kg skater traveling at 2 m/s in the same direction and collides with…
• A train of mass 100 ton is moving up an incline of 1 in 100 at a constant speed of 36 kmph. If the friction per ton is…
• A body of mass m moving with a certain speed suffers a perfectly inelastic collision with a body of mass M at rest. The…
• The potential energy of a particle is represented in the figure. The force acting on the system will be represented by
• If a body of mass 3 kg is dropped from top of a tower of height 250 m, then its kinetic energy after 3 sec. will be
• What is the shape of the graph between the speed and kinetic energy of a body?
• A body is attached to the lower end of a vertical spiral spring and it is gradually lowered to its equilibrium…
• Two balls of different mass have the same kinetic energy. The ball which has the greater linear momentum will be:
• Given below are two statements. STATEMENT - 1: When a spring is compressed, it has elastic potential energy. STATEMENT…
• A spring of spring constant 1000 N/m is compressed through 5 cm and is used to push a metal ball of mass 0.1 kg. The…
• A meter stick of mass 400 g is pivoted at one end hangs vertically. The other end displaced through an angle 60°. The…
• If v be the instantaneous velocity of the body dropped from the top of a tower, when it is located at height h, then…
• When a force is applied on a moving body, its motion is retarded. Then the work done is
• A particle moves under a force F = Cx from x = 0 to x = x 1 . The work done is:
• A body of mass 2 kg moves down the quadrant of a circle of radius 4 m. The velocity on reaching the lowest point is 8…
• A force of (10 i -3 j +6 k ) N acts on a body of 5 kg and displaces it from A (6 i +5 j -3 k ) m to B (10 i -2 j +7 k )…
• A mass M is lowered with the help of a string by a distance x at a constant acceleration g 2 . The magnitude of work…
• A coconut of mass 1.0 kg falls to earth from a height of 10 m. The kinetic energy of the coconut, when it is 4 m above…
• Calculate the K.E. and P.E. of the ball halfway up, when a ball of mass 0.1 kg is thrown vertically upwards with an…
• A block of mass 4 kg falls from a height of 3 m on a spring of force constant l500 N/m. Calculate maximum compression…
• The force required to stretch a spring varies with the distance as shown in the figure. If the experiment is performed…
• The potential energy of a certain spring when stretched through a distance ‘S’ is 10 joules. The amount of work (in…
• A machine gun fires 360 bullets per minute, with a velocity of 600 m/s. If the power of the gun is 5.4 kW, mass of each…
• A body is under the action of two equal and opposite forces, each of 3 N. The body is displaced by 2m. The work done is:
• A block of mass m is pulled along a horizontal surface by applying a force at an angle θ with the horizontal. If the…
• A spring of spring constant 8 N/cm has an extension of 5 cm. The minimum work done in joule in increasing the extension…
• A body is moving under the action of a force. Suddenly, force is increased to such an extent that its kinetic energy is…
• Power applied to a particle varies with time as P = (3t 2 – 2t + 1) W, where t is in second. Find the change in its…
• A running man has half the KE that a boy of half his mass has. The man speeds up by 1m/s and then has the same KE as…
• A body of mass 2 kg is moved from a point A to a point B by an external agent in a conservative force field. If the…
• A particle moves along the x-axis from x = 0 to x = 5 m under the influence of a force given by F = 7 – 2x + 3x 2 …
• If we shift a body in equilibrium from A to C in a gravitational field via path AC or ABC
• Two springs A and B have force constants k A and k B such that k B = 2k A . The four ends of the springs are stretched…
• A 400 g ball is released from a height of 4 m. Each time it makes contact with the ground it loses 25% of its energy…
• Given below are two statements. STATEMENT - 1: Gravitational force is a non-conservative force. STATEMENT - 2: Work…
• If the potential energy of a spring is V on stretching it by 2 cm, then its potential energy when it is stretched by 10…
• A horizonal force F pulls a 10 kg carton across the floor at a constant speed. If the coefficient of sliding friction…
• A ball is dropped from a height 'h' above the floor. If the coefficient of restitution between the floor and the ball…
• A toy gun uses a spring of very large value of force constant k. When charged before triggering in the upward…
• A sphere of mass 2 kg is moving on a frictionless horizontal table with velocity v. It strikes with a spring (force…
• A particle moves on a rough horizontal ground with some initial velocity v_ 0 . If 3 4 th of its K.E. is lost in…
• Under the action of a force, a 2 kg body moves such that its position x as a function of time t is given by x = t^ 3 3…
• A ball of mass 'm' which is moving horizontally at a speed 'v' collides with the bob (of mass m) of a pendulum at rest…
• If the linear momentum is increased by 50%, then kinetic energy will be increased by:
• An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity of 2 ms -1 . The…
• Two springs have their force constants k 1 and k 2 . Both are stretched till their elastic energies are equal. Then…

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