Work, Energy and Power · Physics · NEET
MCQ (Single Correct Answer)
1
The kinetic energies of two similar cars $A$ and $B$ are 100 J and 225 J respectively. On applying breaks, car $A$ stops after 1000 m and car $B$ stops after 1500 m . If $F_A$ and $F_B$ are the forces applied by the breaks on cars $A$ and $B$ respectively, then the ratio of $\frac{F_A}{F_B}$ is
NEET 2025
2
A bob of heavy mass $m$ is suspended by a light string of length $/$. The bob is given a horizontal velocity $v_0$ as shown in figure. If the string gets slack at some point $P$ making an angle $\theta$ from the horizontal, the ratio of the speed $v$ of the bob at point $P$ to its initial speed $v_0$ is:
NEET 2025
3
An object moving along horizontal $$x$$-direction with kinetic energy $$10 \mathrm{~J}$$ is displaced through $$x=(3 \hat{i}) \mathrm{m}$$ by the force $$\vec{F}=(-2 \hat{i}+3 \hat{j}) \mathrm{N}$$. The kinetic energy of the object at the end of the displacement $$x$$ is
NEET 2024 (Re-Examination)
4
An object falls from a height of $$10 \mathrm{~m}$$ above the ground. After striking the ground it loses $$50 \%$$ of its kinetic energy. The height upto which the object can rebounce from the ground is:
NEET 2024 (Re-Examination)
5
At any instant of time $$t$$, the displacement of any particle is given by $$2 t-1$$ ($$\mathrm{SI}$$ unit) under the influence of force of $$5 \mathrm{~N}$$. The value of instantaneous power is (in $$\mathrm{SI}$$ unit):
NEET 2024
6
A particle moves with a velocity $$(5 \hat{i}-3 \hat{j}+6 \hat{k}) ~\mathrm{ms}^{-1}$$ horizontally under the action of constant force $$(10 \hat{\mathrm{i}}+10 \hat{\mathrm{j}}+20 \hat{\mathrm{k}}) \mathrm{N}$$. The instantaneous power supplied to the particle is :
NEET 2023 Manipur
7
The potential energy of a long spring when stretched by $$2 \mathrm{~cm}$$ is U. If the spring is stretched by $$8 \mathrm{~cm}$$, potential energy stored in it will be :
NEET 2023
8
The restoring force of a spring with a block attached to the free end of the spring is represented by
NEET 2022 Phase 2
9
An electric lift with a maximum load of 2000 kg (lift + passengers) is moving up with a constant speed of 1.5 ms$$-$$1. The frictional force opposing the motion is 3000 N. The minimum power delivered by the motor to the lift in watts is : (g = 10 ms$$-$$2)
NEET 2022 Phase 1
10
The energy that will be ideally radiated by a 100 kW transmitter in 1 hour is
NEET 2022 Phase 1
11
A particle is released from height S from the surface of the Earth. At a certain height its kinetic energy is three times its potential energy. The height from the surface of earth and the speed of the particle at that instant are respectively -
NEET 2021
12
Water falls from a height of 60m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine? (g = 10 m/s2)
NEET 2021
13
A force F = 20 + 10y acts on a particle in y-direction where F is in newton and y in meter. Work done by this force to move the particle from y = 0 to y = 1 m is :
NEET 2019
14
A body initially at rest
and sliding along a
frictionless track from
a height h (as shown
in the figure)
just completes a vertical circle of diameter
AB = D. The height h is equal to
NEET 2018
15
Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m s$$-$$1. Take 'g' constant with a value 10 m s$$-$$2. The work done by the (i) gravitational force and the (ii) resistive force of air is
NEET 2017
16
A particle moves from a point $$\left( { - 2\widehat i + 5\widehat j} \right)$$ to $$\left( {4\widehat j + 3\widehat k} \right)$$ when a force of $$\left( {4\widehat i + 3\widehat j} \right)$$ N is applied. How much work has been done by the force ?
NEET 2016 Phase 2
17
What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?
NEET 2016 Phase 1
18
A body of mass 1 kg begins to move under the action of a time dependent force $$\overrightarrow F = \left( {2t\widehat i + 3{t^2}\widehat J} \right)N,$$ where $${\widehat i}$$ and $${\widehat j}$$ are unit vectors along x and y axis. What power will be developed by the force at the time t ?
NEET 2016 Phase 1
19
A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic enegy of the particle becomes equal to 8 $$ \times $$ 10$$-$$4 J by the end of the second revoluation after the beginning of the motion ?
NEET 2016 Phase 1
20
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 density of mercury be 13.6 $$ \times $$ 103 kg/m3 and g = 10 m/s2 then the power (in watt) is
AIPMT 2015
21
Two particles A and B, move with constant velocities $$\overrightarrow {{v_1}} $$ and $$\overrightarrow {{v_2}} $$. At the initial moment their position vectors are $$\overrightarrow {{r_1}} $$ and $$\overrightarrow {{r_2}} $$ respectively. The condition for particles A and B for their collision is
AIPMT 2015
22
On a frictionless surface, a block of mass M moving at speed v collides elastically with another block of same mass M which is initially at rest. After collision the first block moves at an angle $$\theta $$ to its initial direction and has a speed $${v \over 3}.$$ The second block's speed after the collision is
AIPMT 2015
23
A ball is thrown vertically downwards from a height of 20 m with an initial velocity v0. It collides with the ground, losses 50 percent of its energy in collision and rebounds to the same height. The initial velocity v0 is
(Take g = 10 m s$$-$$2)
(Take g = 10 m s$$-$$2)
AIPMT 2015
24
Two similar springs P and Q have spring constants KP and KQ, such that KP > KQ. They are stretched first by the same amount (case a), then by the same force (case b). The work done by the springs WP and WQ are related as, in case (a) and case (b) respectively
AIPMT 2015 Cancelled Paper
25
A particle of mass m is driven by a machine that delivers a constant power k watts. If the particle starts from rest the force on the particle at time t is
AIPMT 2015 Cancelled Paper
26
A block of mass 10 kg, moving in x direction with a constant speed of 10 m s$$-$$1, is subjected to a retarding force F = 0.1x J/m during its travel from x = 20 m to 30 m. Its final KE will be
AIPMT 2015 Cancelled Paper
27
One coolie takes 1 minute to raise a suitcase through a height of 2 m but the second coolie takes 30 s to raise the same suitcase to the same height. The powers of two coolies are in the ratio
NEET 2013 (Karnataka)
28
A particle with total energy E is moving in a potential energy region U(x). Motion of the particle is restricted to the region when
NEET 2013 (Karnataka)
29
A uniform force of $$\left( {3\widehat i + \widehat j} \right)$$ newton acts on a particle of mass 2 kg. Hence the particle is displaced from position $$\left( {2\widehat i + \widehat k} \right)$$ metre to position $$\left( {4\widehat i + 3\widehat j - \widehat k} \right)$$ metre. The work done by the force on the particle is
NEET 2013
30
A car of mass m starts from rest and accelerates so that the instantaneous power delivered to the car has a constant magnitude P0. The instantaneous velocity of this car is proportional to
AIPMT 2012 Mains
31
A solid cylinder of mass 3 kg is rolling on a horizontal surface with velocity 4 m s$$-$$1. It collides with a horizontal spring of force constant 200 N m$$-$$1. The maximum compression produced in the spring will be
AIPMT 2012 Prelims
32
The potential energy of a particle in a force field is $$U = {A \over {{r^2}}} - {B \over r}$$ where A and B are positive constants and r is the distance of particle from the centre of the field. For stable equilibrium, the distance of the particle is
AIPMT 2012 Prelims
33
A mass m moving horizontally (along the x-axis) with velocity $$v$$ collides and sticks to a mass of 3m moving vertically upwards (along the y-axis) with velocity 2$$v$$. The final velocity of the combination is
AIPMT 2011 Mains
34
A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest
AIPMT 2011 Prelims
35
A particle of mass m is released from rest and follows a parabolic path as shown. Assuming that the displacement of the mass from the origin is small, which graph correctly depicts the position of the particle as a function of time ?
AIPMT 2011 Prelims
36
Force F on a particle moving in a straight line varies with distance d as shown in figure.
The work done on the particle during its displacement of 12 m is
The work done on the particle during its displacement of 12 m is
AIPMT 2011 Prelims
37
The potential energy of a system increases if work is done
AIPMT 2011 Prelims
38
A particle of mass M, starting from rest, undergoes uniform acceleration. If the speed acquired in time T is V, the power delivered to the particle is
AIPMT 2010 Mains
39
An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity of 2 m/s. The mass per unit length of water in the pipe is 100 kg/m. What is the power of the engine?
AIPMT 2010 Prelims
40
A ball moving with velocity 2 m/s collides head on with another stationary ball of double the mass. If the coefficient of restitution is 0.5, then their velocities (in m/s) after collision will be
AIPMT 2010 Prelims
41
An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?
AIPMT 2009
42
A block of mass M is attached to the lower end of a vertical spring. The spring is hung from a ceiling and has force constant value k. The mass is released from rest with the spring initially unstretched. The maximum extension produced in the length of the spring will be
AIPMT 2009
43
A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? (g = 10 m/s2)
AIPMT 2009
44
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional forces are 10% of energy. How much power is generated by the turbine ? (g = 10 m/s2)
AIPMT 2008
45
A vertical spring with force constant k is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d. The net work done in the process is
AIPMT 2007
46
The potential energy of a long spring when stretched by 2 cm is U. If the spring is stretched by 8 cm the potential energy stored in it is
AIPMT 2006
47
A body of mass 3 kg is under a constant force which causes a displacement s in metres in it, given by the relation s = $${1 \over 3}$$t2, where t is in seconds. Work done by the force in 2 seconds is
AIPMT 2006
48
300 J of work is done in sliding a 2 kg block up an inclined plane of height 10 m. Work done against friction is (Take g = 10 m/s2)
AIPMT 2006
49
A force F acting
on an object varies with distance x as shown here. The force is in N and x in m. The work done by the force in moving the object from x = 0 to x = 6 m is
on an object varies with distance x as shown here. The force is in N and x in m. The work done by the force in moving the object from x = 0 to x = 6 m is
AIPMT 2005
50
A mass of 0.5 kg moving with a speed of 1.5 m/s on horizontal smooth surface, collides with a nearly weightless spring of force constant k = 50 N/m. The maximum compression of the spring would be
AIPMT 2004
51
A particle of mass m1 is moving with a velocity v1 and another particle of mass m2 is moving with a velocity v2. Both of them have the same momentum but their different kinetic energies are E1 and E2 respectively. If m1 > m2 then :
AIPMT 2004
52
A ball of mass 2 kg and another of mass 4 kg are dropped together from a 60 feet ball building. After a fall of 30 feet each towards earth, their respective kinetic energies will be in the ratio of
AIPMT 2004
53
A particle moves along a circle of radius $$\left( {{{20} \over \pi }} \right)$$ m with constants tangential acceleration. If the velocity of vthe particle is 80 m/s at the end of the second revoluation after motion has begun, the tangential acceleration is
AIPMT 2003
54
When a long spring is stretched by 2 cm, its potential energy is U. If the spring is stretched by 10 cm, the potential energy stored in it will be
AIPMT 2003
55
Two springs A and B having spring constant KA and KB (KA = 2KB) are stretched by applying force of equal magnitude. If energy stored in spring A is EA then energy stored in B will be
AIPMT 2001
56
A particle is projected making an angle of 45o with horizontal having kinetic energy K. The kinetic energy at highest point will be
AIPMT 2001
57
A child is sitting on a swing. Its minimum and maximum heights from the ground 0.75 m and 2 m respectively, its maximum speed will be
AIPMT 2001
58
A mass of 1 kg is thrown up with a velocity of 100 m/s. After 5 seconds, it explodes into two parts. One part of mass 400 g comes down with a velocity 25 m/s. The velocity of other part is (Take g = 10 ms$$-$$2)
AIPMT 2000
59
If $$\overrightarrow F = \left( {60\widehat i + 15\widehat j - 3\widehat k} \right)$$ N and $$\overrightarrow v = \left( {2\widehat i - 4\widehat j + 5\widehat k} \right)$$ m/s, then instantaneous power is
AIPMT 2000