JEE Main
Physics
Work Power & Energy
Previous Years Questions

## Numerical

A block is fastened to a horizontal spring. The block is pulled to a distance $$x=10 \mathrm{~cm}$$ from its equilibrium position (at $$x=0$$) on a fr...
A force $$\mathrm{F}=\left(5+3 y^{2}\right)$$ acts on a particle in the $$y$$-direction, where $$\mathrm{F}$$ is in newton and $$y$$ is in meter. The ...
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 for...
A lift of mass $$\mathrm{M}=500 \mathrm{~kg}$$ is descending with speed of $$2 \mathrm{~ms}^{-1}$$. Its supporting cable begins to slip thus allowing ...
A body of mass $2 \mathrm{~kg}$ is initially at rest. It starts moving unidirectionally under the influence of a source of constant power P. Its displ...
A 0.4 kg mass takes 8s to reach ground when dropped from a certain height 'P' above surface of earth. The loss of potential energy in the last second ...
An object of mass 'm' initially at rest on a smooth horizontal plane starts moving under the action of force F = 2N. In the process of its linear moti...
A body of mass 1kg begins to move under the action of a time dependent force $$\overrightarrow F = \left( {t\widehat i + 3{t^2}\,\widehat j} \right)... A spherical body of mass 2 kg starting from rest acquires a kinetic energy of 10000 J at the end of$$\mathrm{5^{th}}$$second. The force acted on the... A block of mass '$$\mathrm{m}$$' (as shown in figure) moving with kinetic energy E compresses a spring through a distance$$25 \mathrm{~cm}$$when, it... A uniform chain of 6 m length is placed on a table such that a part of its length is hanging over the edge of the table. The system is at rest. The co... A 0.5 kg block moving at a speed of 12 ms$$-$$1 compresses a spring through a distance 30 cm when its speed is halved. The spring constant of the spri... A ball of mass 100 g is dropped from a height h = 10 cm on a platform fixed at the top of a vertical spring (as shown in figure). The ball stays on th... An engine is attached to a wagon through a shock absorber of length 1.5 m. The system with a total mass of 40,000 kg is moving with a speed of 72 kmh... A block moving horizontally on a smooth surface with a speed of 40 ms$$-$$1 splits into two equal parts. If one of the parts moves at 60 ms$$-$$1 in t... Two persons A and B perform same amount of work in moving a body through a certain distance d with application of forces acting at angle 45$$^\circ$$... A uniform chain of length 3 meter and mass 3 kg overhangs a smooth table with 2 meter lying on the table. If k is the kinetic energy of the chain in j... A small block slides down from the top of hemisphere of radius R = 3 m as shown in the figure. The height 'h' at which the block will lose contact wit... A force of F = (5y + 20)$$\widehat j$$N acts on a particle. The work done by this force when the particle is moved from y = 0 m to y = 10 m is ______... In the reported figure, two bodies A and B of masses 200 g and 800 g are attached with the system of springs. Springs are kept in a stretched position... In a spring gun having spring constant 100 N/m a small ball 'B' of mass 100 g is put in its barrel (as shown in figure) by compressing the spring thro... A ball of mass 4 kg, moving with a velocity of 10 ms$$-$$1, collides with a spring of length 8 m and force constant 100 Nm$$-$$1. The length of the co... As shown in the figure, a particle of mass 10 kg is placed at a point A. When the particle is slightly displaced to its right, it starts moving and re... A boy pushes a box of mass 2 kg with a force$$\overrightarrow F = \left( {20\widehat i + 10\widehat j} \right)N$$on a frictionless surface. If the ... The potential energy (U) of a diatomic molecule is a function dependent on r (interatomic distance) as$$U = {\alpha \over {{r^{10}}}} - {\beta \ove...
A body of mass 2 kg is driven by an engine delivering a constant power of 1 J/s. The body starts from rest and moves in a straight line. After 9 secon...
A block starts moving up an inclined plane of inclination 30o with an initial velocity of v0 . It comes back to its initial position with velocity $${... A cricket ball of mass 0.15 kg is thrown vertically up by a bowling machine so that it rises to a maximum height of 20 m after leaving the machine. If... A small block starts slipping down from a point B on an inclined plane AB, which is making an angle$$\theta $$with the horizontal section BC is smo... A body A, of mass m = 0.1 kg has an initial velocity of 3$$\widehat i$$ms-1 . It collides elastically with another body, B of the same mass which has... A particle (m = 1 kg) slides down a frictionless track (AOC) starting from rest at a point A (height 2 m). After reaching C, the particle continues to... ## MCQ (Single Correct Answer) Identify the correct statements from the following : A. Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket is ... A stone is projected at angle$$30^{\circ}$$to the horizontal. The ratio of kinetic energy of the stone at point of projection to its kinetic energy ... A ball is projected with kinetic energy E, at an angle of$$60^{\circ}$$to the horizontal. The kinetic energy of this ball at the highest point of it... A bullet of mass$$200 \mathrm{~g}$$having initial kinetic energy$$90 \mathrm{~J}$$is shot inside a long swimming pool as shown in the figure. If i... Sand is being dropped from a stationary dropper at a rate of$$0.5 \,\mathrm{kgs}^{-1}$$on a conveyor belt moving with a velocity of$$5 \mathrm{~ms}...
As per the given figure, two blocks each of mass $$250 \mathrm{~g}$$ are connected to a spring of spring constant $$2 \,\mathrm{Nm}^{-1}$$. If both ar...
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 ene...
A body of mass $$0.5 \mathrm{~kg}$$ travels on straight line path with velocity $$v=\left(3 x^{2}+4\right) \mathrm{m} / \mathrm{s}$$. The net workdone...
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 ...
A particle of mass 500 gm is moving in a straight line with velocity v = b x5/2. The work done by the net force during its displacement from x = 0 to ...
A lead bullet penetrates into a solid object and melts. Assuming that 40% of its kinetic energy is used to heat it, the initial speed of bullet is : (...
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 ...
In the arrangement shown in figure a1, a2, a3 and a4 are the accelerations of masses m1, m2, m3 and m4 respectively. Which of the following relation i...
Arrange the four graphs in descending order of total work done; where W1, W2, W3 and W4 are the work done corresponding to figure a, b, c and d respec...
Potential energy as a function of r is given by $$U = {A \over {{r^{10}}}} - {B \over {{r^5}}}$$, where r is the interatomic distance, A and B are pos...
A particle experiences a variable force $$\overrightarrow F = \left( {4x\widehat i + 3{y^2}\widehat j} \right)$$ in a horizontal x-y plane. Assume di...
A body of mass 'm' dropped from a height 'h' reaches the ground with a speed of 0.8$$\sqrt {gh}$$. The value of workdone by the air-friction is :
A block moving horizontally on a smooth surface with a speed of 40 m/s splits into two parts with masses in the ratio of 1 : 2. If the smaller part mo...
Given below is the plot of a potential energy function U(x) for a system, in which a particle is in one dimensional motion, while a conservative force...
An automobile of mass 'm' accelerates starting from origin and initially at rest, while the engine supplies constant power P. The position is given as...
A porter lifts a heavy suitcase of mass 80 kg and at the destination lowers it down by a distance of 80 cm with a constant velocity. Calculate the wor...
A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time 't' is propo...
A constant power delivering machine has towed a box, which was initially at rest, along a horizontal straight line. The distance moved by the box in t...
A boy is rolling a 0.5 kg ball on the frictionless floor with the speed of 20 ms-1. The ball gets deflected by an obstacle on the way. After deflectio...
If two similar springs each of spring constant K1 are joined in series, the new spring constant and time period would be changed by a factor :...
If the potential energy between two molecules is given by U = $$- {A \over {{r^6}}} + {B \over {{r^{12}}}}$$, then at equilibrium, separation between...
A person pushes a box on a rough horizontal plateform surface. He applies a force of 200 N over a distance of 15 m. Thereafter, he gets progressively ...
Blocks of masses m, 2m, 4m and 8m are arranged in a line on a frictionless floor. Another block of mass m, moving with speed v along the same line (se...
A particle is moving unidirectionally on a horizontal plane under the action of a constant power supplying energy source. The displacement (s) - time ...
A block of mass 1.9 kg is at rest at the edge of a table, of height 1 m. A bullet of mass 0.1 kg collides with the block and sticks to it. If the velo...
A particle of mass m with an initial velocity $$u\widehat i$$ collides perfectly elastically with a mass 3 m at rest. It moves with a velocity $$v\wid... Consider a force$$\overrightarrow F = - x\widehat i + y\widehat j$$. The work done by this force in moving a particle from point A(1, 0) to B(0, 1... An elevator in a building can carry a maximum of 10 persons, with the average mass of each person being 68 kg, The mass of the elevator itself is 920 ... A 60 HP electric motor lifts an elevator having a maximum total load capacity of 2000 kg. If the frictional force on the elevator is 4000 N, the speed... As shown in the figure, a bob of mass m is tied by a massless string whose other end portion is wound on a fly wheel (disc) of radius r and mass m. W... A spring whose unstretched length is l has a force constant k. The spring is cut into two pieces of unstretched lengths l1 and l2 where, l1 = nl2 and ... A massless spring (k = 800 N/m), attached with a mass (500 g) is completely immersed in 1 kg of water. The spring is stretched by 2 cm and released so... A wedge of mass M = 4m lies on a frictionless plane. A particle of mass m approaches the wedge with speed v. There is no friction between the particle... The following bodies are made to roll up (without slipping) the same inclined plane from a horizontal plane. : (i) a ring of radius R, (ii) a solid cy... A uniform cable of mass 'M' and length 'L' is placed on a horizontal surface such that its (1/n)th part is hanging below the edge of the surface. To l... A solid sphere and solid cylinder of identical radii approach an incline with the same linear velocity (see figure). Both roll without slipping all th... A particle moves in one dimension from rest under the influence of a force that varies with the distance travelled by the particle as shown in the fig... A particle of mass 20 g is released with an initial velocity 5 m/s along the curve from the point A, as shown in the figure. The point A is at height ... An alpha-particle of mass m suffers 1-dimensional elastic collision with a nucleus at rest of unknown mass. It is scattered directly backwards losing,... For the given cyclic process CAB as shown for a gas, the work done is : ... There is a uniform spherically symmetric surface charge density at a distance R0 from the origin. The charge distribution is initially at rest and sta... A body of mass 1 kg falls freely from a height of 100 m, on a platform mass 3 kg which is mounted on a spring having spring constant k = 1.25$$ \time...
A particle which is experiencing a force, given by $$\overrightarrow F = 3\widehat i - 12\widehat j,$$ undergoes a displacement of $$\overrightarrow ... A block of mass m is kept on a platform which starts from rest with constant acceleration g/2 upward, as shown in figure. Work done by normal reaction... A force acts on a 2 kg object so that its position is given as a function of time as x = 3t2 + 5. What is the work done by this force in first 5 secon... A block of mass m, lying on a smooth horizontal surface, is attached to a sring (of negligible mass) of spring constant k. The other end of the spring... Three blocks A, B and C are lying on a smooth horizontal surface, as shown in the figure. A and B have equal masses, m while C has mass M, Block A is ... Two particles of the same mass m are moving in circular orbits because of force, given by$$F\left( r \right) = {{ - 16} \over r} - {r^3}$$The first ... A body of mass m starts moving from rest along x-axis so that its velocity varies as$$\upsilon = a\sqrt s $$where a is a constant and s is the dist... In a collinear collision, a particle with an initial speed v0 strikes a stationary particle of the same mass. If the final total kinetic energy is 50%... A proton of mass m collides elastically with a particle of unknown mass at rest. After the collision, the proton and the unknown particle are seen mo... Two particles A and B of equal mass M are moving with the same speed$$\upsilon $$as shown in the figure. They collide completely inelastically and m... An object is dropped from a height h from the ground. Every time it hits the ground it looses 50% of its kinetic energy. The total distance covered as... A body of mass m = 10–2 kg is moving in a medium and experiences a frictional force F = –kv2. Its initial speed is v0 = 10 ms–1. If, after 10 s, its e... A time dependent force F = 6t acts on a particle of mass 1 kg. If the particle starts from rest, the work done by the force during the first 1 sec. wi... A particle of mass M is moving in a circle of fixed radius R in such a way that its centripetal acceleration at time t is given by n2 R t2 where n is ... A neutron moving with a speed ‘v’ makes a head on collision with a stationary hydrogen atom in ground state. The minimum kinetic energy of the neutron... Velocity-time graph for a body of mass 10 kg is shown in figure. Work-done on the body in first two seconds of the motion is : ... A car of weight W is on an inclined road that rises by 100 m over a distance of 1 km and applies a constant frictional force$${W \over 20}$$on the c... A person trying to lose weight by burning fat lifts a mass of$$10kg$$upto a height of$$1m1000$$times. Assume that the potential ene... A point particle of mass$$m,$$moves long the uniformly rough track$$PQR$$as shown in the figure. The coefficient of friction, between the particle... When a rubber-band is stretched by a distance$$x$$, it exerts restoring force of magnitude$$F = ax + b{x^2}$$where$$a$$and$$b$$are constants. T... This question has Statement$$1$$and Statement$$2.$$Of the four choices given after the Statements, choose the one that best describes the two Stat... The potential energy function for the force between two atoms in a diatomic molecule is approximately given by$$U\left( x \right) = {a \over {{x^{12}...
A block of mass $$0.50$$ $$kg$$ is moving with a speed of $$2.00$$ $$m{s^{ - 1}}$$ on a smooth surface. It strike another mass of $$1.0$$ $$kg$$ and t...
An athlete in the olympic games covers a distance of $$100$$ $$m$$ in $$10$$ $$s.$$ His kinetic energy can be estimated to be in the range
A particle is projected at $$60^\circ$$ to the horizontal with a kinetic energy K. The kinetic energy at the highest point is
A $$2$$ $$kg$$ block slides on a horizontal floor with a speed of $$4m/s.$$ It strikes a uncompressed spring, and compress it till the block is motion...
A mass of $$M$$ $$kg$$ is suspended by a weightless string. The horizontal force that is required to displace it until the string makes an angle of $$... A ball of mass$$0.2kg$$is thrown vertically upwards by applying a force by hand. If the hand moves$$0.2m$$while applying the force and t... A particle of mass$$100g$$is thrown vertically upwards with a speed of$$5m/s$$. The work done by the force of gravity during the time the part... The potential energy of a$$1kg$$particle free to move along the$$x$$-axis is given by$$V\left( x \right) = \left( {{{{x^4}} \over 4} - {{{x^2...
A bullet fired into a fixed target loses half of its velocity after penetrating $$3$$ $$cm.$$ How much further it will penetrate before coming to rest...
The upper half of an inclined plane with inclination $$\phi$$ is perfectly smooth while the lower half is rough. A body starting from rest at the top...
A body of mass $$m$$ is accelerated uniformly from rest to a speed $$v$$ in a time $$T.$$ The instantaneous power delivered to the body as a function ...
A spherical ball of mass $$20$$ $$kg$$ is stationary at the top of a hill of height $$100$$ $$m$$. It rolls down a smooth surface to the ground, then...
The block of mass $$M$$ moving on the frictionless horizontal surface collides with the spring of spring constant $$k$$ and compresses it by length $$... A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement$$x$$is propor... A uniform chain of length$$2m$$is kept on a table such that a length of$$60cm$$hangs freely from the edge of the table. The total mass ... A force$$\overrightarrow F = \left( {5\overrightarrow i + 3\overrightarrow j + 2\overrightarrow k } \right)N$$is applied over a particle which di... A body of mass$$' m ',$$acceleration uniformly from rest to$$'{v_1}'$$in time$${T}$$. The instantaneous power delivered to the body as a function... A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particles t... Consider the following two statements:$$A.\,\,\,\,\,\,$$Linear momentum of a system of particles is zero$$B.\,\,\,\,\,\,$$Kinetic energy ... A spring of spring constant$$5 \times {10^3}\,N/m$$is stretched initially by$$5cm$$from the unstretched position. Then the work required to s... A wire suspended vertically from one of its ends is stretched by attaching a weight of$$200N$$to the lower end. The weight stretches the wire by$$1...
A body is moved along a straight line by a machine delivering a constant power. The distance moved by the body in time $$'t'$$ is proportional to
A ball whose kinetic energy E, is projected at an angle of $$45^\circ$$ to the horizontal. The kinetic energy of the ball at the highest point of its...
If a body looses half of its velocity on penetrating $$3$$ $$cm$$ in a wooden block, then how much will it penetrate more before coming to rest?
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
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