# Solved papers for NEET Physics Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति NEET PYQ-Work Energy Power and Collision

### done NEET PYQ-Work Energy Power and Collision Total Questions - 49

• question_answer1) A force acts on a 3.0 g particle in such a way that the position of the particle as a function of time is given by $x=3t-4{{t}^{2}}+{{t}^{3}},$ where $x$ is in metre and $t$ in second. The work done during the first 4 s is: [AIPMT 1998]

A)
570 mJ

B)
450 mJ

C)
490 mJ

D)
528 mJ

• question_answer2) Two equal masses ${{m}_{1}}$ and ${{m}_{2}}$ moving along the same straight line with velocities $+\text{ }3\text{ }m/s$ and $\,\,5\text{ }m/s$ respectively collide elastically. Their velocities after the collision will be respectively: [AIPMT 1998]

A)
$+\text{ }4\text{ }m/s$for both

B)
$-\,3\,\,m/s$ and $+\text{ }5\text{ }m/s$

C)
$-\text{ }4\text{ }m/s$ and $+4\text{ }m/s~$

D)
$-\text{ }5\text{ }m/s$ and $+\text{ }3\text{ }m/s$

• question_answer3) A weightless ladder 20 ft long rests against a frictionless wall at an angle of ${{60}^{o}}$ from the horizontal. A 150 pound man is 4 ft from the top of the ladder. A horizontal force is needed to keep it from slipping. Choose the correct magnitude of force from the following:                    [AIPMT 1998]

A)
17.3 pound

B)
100 pound

C)
120 pound

D)
150 pound

• question_answer4) A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of: [AIPMT 1998]

A)
$\frac{16}{25}$

B)
$\frac{2}{5}$

C)
$\frac{3}{5}$

D)
$\frac{9}{25}$

• question_answer5) An engine exerts a force $\vec{F}=(20\hat{i}-3\hat{j}+5\hat{k})N$ and moves with velocity$\vec{v}=(6\hat{j}+20\hat{j}-3\hat{k})\,m/s$.  The power of the engine (in watt) is: [AIPMT 2000]

A)
45

B)
75

C)
20

D)
10

• question_answer6)  A stone is attached to one end of a string and rotated in a vertical circle. If string breaks at the position of maximum tension, it will break at: [AIPMT 2000]

A)
A

B)
B

C)
C

D)
D

• question_answer7) A man goes at the top of a smooth inclined plane. He releases a bag to fall freely and he himself slides on inclined plane to reach the bottom. If ${{v}_{1}}$ and ${{v}_{2}}$ are the velocities of the man and bag respectively, then: [AIPMT 2000]

A)
${{v}_{1}}>{{v}_{2}}$

B)
${{v}_{1}}<{{v}_{2}}$

C)
${{v}_{1}}={{v}_{2}}$

D)
${{v}_{1}}$ and ${{v}_{2}}$ cannot be compared

• question_answer8) A child is swinging a swing. Minimum and maximum heights of swing from earths surface are 0.75 m and 2 m respectively. The maximum velocity of this swing is:                       [AIPMT 2001]

A)
5 m/s

B)
10 m/s

C)
15 m/s

D)
20 m/s

• question_answer9) A force of 250 N is required to lift a 75 kg mass through a pulley system. In order to lift the mass through 3 m, the rope has to be pulled through 12 m. The efficiency of system is: [AIPMT 2001]

A)
50%

B)
75%

C)
33%

D)
90%

• question_answer10) Two springs A and B have force constants ${{k}_{A}}$ and ${{k}_{B}}$ such that ${{k}_{B}}=2\,{{k}_{A}}$. The four ends of the springs are stretched by the same force, If energy stored in spring A is E, then energy stored in spring B is:                         [AIPMT 2001]

A)
E/2

B)
2 E

C)
E

D)
4 E

• question_answer11) If kinetic energy of a body is increased by 300% then percentage change in momentum will be: [AIPMT 2002]

A)
100%

B)
150%

C)
265%

D)
73.2%

• question_answer12) 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 in it will be: [AIPMT 2003]

A)
10 U

B)
25 U

C)
U/5

D)
5 U

• question_answer13)  A mass of 0.5 kg moving with a speed of 1.5 m/son a horizontal smooth surface, collides with a nearly weightless spring of force constant $k=50\text{ }N/m$. The maximum compression of the spring would be:[AIPMT (S) 2004]

A)
0.15 m

B)
0.12 m

C)
1.5 m

D)
0.5 m

• question_answer14) A stone is tied to a string of length $l$ and is whirled in a vertical circle with the other end of the string as the centre. At a certain instant of time, the stone is at its lowest position and has a speed $u$. The magnitude of the change in velocity as it reaches a position where the string is horizontal {g being acceleration due to gravity) is:  [AIPMT (S) 2004]

A)
$\sqrt{2({{u}^{2}}-gl)}$

B)
$\sqrt{{{u}^{2}}-gl}$

C)
$u-\sqrt{{{u}^{2}}-2gl}$

D)
$\sqrt{2gl}$

• question_answer15) A particle of mass ${{m}_{1}}$ is moving with a velocity ${{v}_{1}}$ and another particle of mass ${{m}_{2}}$ is moving with a velocity ${{v}_{2}}$. Both of them have the same momentum but their different kinetic energies are ${{E}_{1}}$ and ${{E}_{2}}$ respectively. If ${{m}_{1}}>{{m}_{2}}$ then: [AIPMT (S) 2004]

A)
${{E}_{1}}<{{E}_{2}}$

B)
$\frac{{{E}_{1}}}{{{E}_{2}}}=\frac{{{m}_{1}}}{{{m}_{2}}}$

C)
${{E}_{1}}>{{E}_{2}}$

D)
${{E}_{1}}={{E}_{2}}$

• question_answer16)  A force F acting on an object varies with distance $x$ as shown here. The force is in N and $x$ is in m. The work done by the force in moving the object from $x=0$ to $x=6\,m$ is: [AIPMT (S) 2005]

A)
4.5 J

B)
13.5 J

C)
9.0 J

D)
18.0 J

• question_answer17) 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 (S) 2006]

A)
4 U

B)
8 U

C)
16 U

D)
U/4

• question_answer18) A body of mass 3 kg is under a constant force which causes a displacement s in metres in it, given by the relation $s=\frac{1}{3}\,{{t}^{2}},$ where t is in s. Work done by the force in 2 s is :

A)
$\frac{5}{19}\,J$

B)
$\frac{3}{18}\,J$

C)
$\frac{8}{3}\,J$

D)
$\frac{19}{5}\,J$

• question_answer19) 300 J of work is done in sliding a 2 kg block up an inclined plane of height 10 m. Taking $g=10\,m/{{s}^{2}}$, work done against friction is : [AIPMT (S) 2006]

A)
200 J

B)
100 J

C)
zero

D)
1000 J

• question_answer20) A vertical spring with force constant k is fixed on a table. A ball of mass m at a height ft 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 (S) 2007]

A)
$mg(h+d)+\frac{1}{2}k{{d}^{2}}$

B)
$mg(h+d)-\frac{1}{2}k{{d}^{2}}$

C)
$mg(h-d)-\frac{1}{2}k{{d}^{2}}$

D)
$mg(h-d)+\frac{1}{2}k{{d}^{2}}$

• question_answer21) A roller coaster is designed such that riders experience weightlessness as they go round the top of a hill whose radius of curvature is 20 m. The speed of the car at the top of the hill is between            [AIPMPT (S) 2008]

A)
14 m/s and 15 m/s

B)
15 m/s  and 16 m/s

C)
16 m/s and 17 m/s

D)
13 m/s  and 14 m/s

• question_answer22) A body of mass 1 kg is thrown upwards with a velocity $20\,m{{s}^{-1}}$. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? $(g=10\,m{{s}^{-1}})$ [AIPMT (S) 2009]

A)
20 J

B)
30 J

C)
40 J

D)
10 J

• question_answer23) 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 (S) 2009]

A)
$\frac{1}{2}\,m{{v}^{3}}$

B)
$m{{v}^{3}}$

C)
$\frac{1}{2}m{{v}^{2}}$

D)
$\frac{1}{2}{{m}^{2}}{{v}^{2}}$

• question_answer24) 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 un stretched. The maximum extension produced in the length of the spring will be [AIPMT (S) 2009]

A)
$Mg/k$

B)
$-\,2\text{ }Mg/k~$

C)
$4\,\,Mg/k$

D)
$Mg/2k$

• question_answer25) 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 (M) 2010]

A)
$\frac{M{{v}^{2}}}{T}$

B)
$\frac{1}{2}\frac{M{{v}^{2}}}{{{T}^{2}}}$

C)
$\frac{M{{v}^{2}}}{{{T}^{2}}}$

D)
$\frac{1}{2}\frac{M{{v}^{2}}}{T}$

• question_answer26) A mass m moving horizontally (along the x-axis) with velocity v collides and sticks to mass of 3 m moving vertically upward (along the y-axis) with velocity 2v. The final velocity of the combination is     [AIPMT (M) 2011]

A)
$\frac{1}{4}v\mathbf{\hat{i}}+\frac{3}{2}v\mathbf{\hat{j}}$

B)
$\frac{1}{3}v\mathbf{\hat{i}}+\frac{2}{3}v\mathbf{\hat{j}}$

C)
$\frac{2}{3}v\mathbf{\hat{i}}+\frac{1}{3}v\mathbf{\hat{j}}$

D)
$\frac{3}{2}v\mathbf{\hat{i}}+\frac{1}{4}v\mathbf{\hat{j}}$

• question_answer27) 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 (S) 2011]

A)
at the instant just before the body hits the earth

B)
it remains constant all through

C)
at the instant just after the body is projected

D)
at the highest position of the body

• question_answer28) The potential energy of a system increase if work is done                                [AIPMT (S) 2011]

A)
by the system against a conservative force

B)
by the system against a neoconservative force

C)
upon the system by a conservative force

D)
upon the system by a neoconservative force

• question_answer29)  Force F on a particle moving in a straight line varies with distance d as shown in the figure. The work done on the particle during its displacement of 12 m is                   [AIPMT (S) 2011]

A)
21 J

B)
26 J

C)
13 J

D)
18 J

• question_answer30) A car of mass m starts from rest and accelerates so that the instantaneous power delivered to the car has a constant magnitude ${{p}_{0}}$. The instantaneous velocity of this car is proportional to                         [AIPMT (M) 2012]

A)
${{t}^{2}}{{p}_{0}}$

B)
${{t}^{1/2}}$

C)
${{t}^{-1/2}}$

D)
$t/\sqrt{m}$

• question_answer31) The potential energy of a particle in a force field is $U=\frac{A}{{{r}^{2}}}-\frac{A}{r},$ 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 (S) 2012]

A)
B/2A

B)
2A/B

C)
A/B

D)
B/A

• question_answer32)  Two spheres A and B of masses ${{m}_{1}}$ and ${{m}_{2}}$ respectively collide. A is at rest initially and B is moving with-velocity v along x-axis. After collision B has a velocity $\frac{v}{2}$ in a direction perpendicular to the original direction. The mass A moves after collision in the direction [AIPMT (S) 2012]

A)
same as that of B

B)
opposite to that of B

C)
$\theta ={{\tan }^{-1}}\left( \frac{1}{2} \right)$ to the x-axis

D)
$\theta ={{\tan }^{-1}}\left( \frac{-1}{2} \right)$

• question_answer33) A uniform force of $(3\mathbf{i}+\mathbf{j})\,N$ acts on a particle of mass 2 kg. Hence the particle is displaced from position $(2\mathbf{i}+\mathbf{k})\,m$ to position $(4\mathbf{i}+3\mathbf{j}-\mathbf{k})\,m$. The work done by the force on the particle is [NEET 2013]

A)
9 J

B)
6 J

C)
13 J

D)
15 J

• question_answer34)  Two similar springs P and Q have spring constants ${{K}_{P}}$ and ${{K}_{Q}},$ such that ${{K}_{P}}>{{K}_{Q}}$. They are stretched, first by the same amount (case a), then by the same force (case b). The work done by the springs ${{W}_{P}}$ and ${{W}_{Q}}$ are related as, in case and case , respectively                   [NEET 2015 ]

A)
${{W}_{P}}={{W}_{Q}};{{W}_{P}}>{{W}_{Q}}$

B)
${{W}_{P}}={{W}_{Q}};{{W}_{P}}={{W}_{Q}}$

C)
${{W}_{P}}>{{W}_{Q}};{{W}_{Q}}>{{W}_{P}}$

D)
${{W}_{P}}<{{W}_{Q}};{{W}_{Q}}<{{W}_{P}}$

• question_answer35) 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 $F=0.1\,\times \,J/m$ during its travel from $x=20\,m$ to 30 m. Its final KE will be [NEET 2015 ]

A)
475 J

B)
450 J

C)
275 J

D)
250 J

• question_answer36) 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                                   [NEET 2015 ]

A)
$\sqrt{\frac{mk}{2}}\,{{t}^{{}^{1}/{}_{2}}}$

B)
$\sqrt{mk}\,{{t}^{{}^{-1}/{}_{2}}}$

C)
$\sqrt{2mk}\,{{t}^{{}^{-1}/{}_{2}}}$

D)
$\frac{1}{2}\sqrt{mk}\,{{t}^{{}^{-1}/{}_{2}}}$

• question_answer37) Two particles of masses ${{m}_{1}},{{m}_{2}}$ move with initial velocities ${{u}_{1}}$ and ${{u}_{2}}$. On collision, one of the particles get excited to higher level, after absorbing energy $\varepsilon$. If final velocities of particles be ${{v}_{1}}$ and ${{v}_{2}},$ then we must have [NEET 2015 ]

A)
$m_{1}^{2}{{u}_{1}}+m_{2}^{2}{{u}_{2}}-\varepsilon =m_{1}^{2}{{v}_{1}}+m_{2}^{2}{{v}_{2}}$

B)
$\frac{1}{2}{{m}_{1}}u_{1}^{2}+\frac{1}{2}{{m}_{2}}u_{2}^{2}=\frac{1}{2}{{m}_{1}}v_{1}^{2}+\frac{1}{2}{{m}_{2}}v_{2}^{2}-\varepsilon$

C)
$\frac{1}{2}{{m}_{1}}u_{1}^{2}+\frac{1}{2}{{m}_{2}}u_{2}^{2}-\varepsilon =\frac{1}{2}{{m}_{1}}v_{1}^{2}+\frac{1}{2}{{m}_{2}}v_{2}^{2}$

D)
$\frac{1}{2}m_{1}^{2}u_{1}^{2}+\frac{1}{2}m_{2}^{2}u_{2}^{2}+\varepsilon =\frac{1}{2}m_{1}^{2}v_{1}^{2}+\frac{1}{2}m_{2}^{2}v_{2}^{2}$

• question_answer38) A ball is thrown vertically downwards from a height of 20 m with an initial velocity ${{V}_{0}}$. It collides with the ground, loses 50% of its energy in collision and rebounds to the same height. The initial velocity ${{V}_{0}}$ is (Take,$g=10m{{s}^{-2}}$)        [NEET 2015 (Re)]

A)
$14\,\,m{{s}^{-1}}$

B)
$20\,\,m{{s}^{-1}}$

C)
$28\,\,m{{s}^{-1}}$

D)
$10\,\,m{{s}^{-1}}$

• question_answer39) 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 $\frac{v}{3}$. The second block's speed after the collision is          [NEET 2015 (Re)]

A)
$\frac{2\sqrt{2}}{3}v$

B)
$\frac{3}{4}v$

C)
$\frac{3}{\sqrt{2}}v$

D)
$\frac{\sqrt{3}}{2}v$

• question_answer40) 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]

A)
$\sqrt{gR}$

B)
$\sqrt{2gR}$

C)
$\sqrt{3gR}$

D)
$\sqrt{5gR}$

• question_answer41) A body of mass 1 kg begins to move under the action of a time dependent force $\vec{F}=(2t\,\mathbf{\hat{i}}\,+3{{t}^{2}}\,\mathbf{\hat{j}})N,$ where $\mathbf{\hat{i}}$ and $\mathbf{\hat{j}}$ are unit vectors along x and y axis. What power will be developed by the force at the time t? [NEET - 2016]

A)
$(2{{t}^{2}}+3{{t}^{3}})W$

B)
$(2{{t}^{2}}+4{{t}^{4}})W$

C)
$(2{{t}^{3}}+3{{t}^{4}})W$

D)
$(2{{t}^{3}}+3{{t}^{5}})W$

• question_answer42)  Two blocks A and B of masses 3 m and m respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of A and B immediately after the string is cut, are respectively [NEET  2017]

A)
$\frac{g}{3},\frac{g}{3}$

B)
$g,\frac{g}{3}$

C)
$\frac{g}{3},g$

D)
$g,\,g$

• question_answer43) The bulk modulus of a spherical object is $'B'$. If it is subjected to uniform pressure $'p',$ the fractional decrease in radius is            [NEET-2017]

A)
$\frac{\rho }{3B}$

B)
$\frac{\rho }{B}$

C)
$\frac{B}{3p}$

D)
$\frac{3p}{B}$

• question_answer44) One end of string of length l is connected to a particle of mass m and the other end is connected to a small peg on a smooth horizontal table. If the particle moves in circle with speed v, the net force on the particle (directed towards center) will be (T represents the tension in the string)                                     [NEET-2017]

A)
Zero

B)
T

C)
$T+\frac{m{{v}^{2}}}{l}$

D)
$T-\frac{m{{v}^{2}}}{l}$

• question_answer45) 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. 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

A)
(i) 10 J, (ii) $-8.75\,J$

B)
(i)  10 J, (ii) $\text{ }8.25\text{ }J$

C)
(i) 1.25 J , (ii) $\text{ }8.25\text{ }J$

D)
(i) 100 J, (ii) 8.75 J

• question_answer46) A moving block having mass m, collides with another stationary block having mass 4m. The lighter block comes to rest after collision. When the initial velocity of the lighter block is v, then the value of coefficient of restitution (e) will be [NEET - 2018]

A)
0.8

B)
0.25

C)
0.5

D)
0.4

• question_answer47) Body A of mass 4m moving with speed u collides with another body B of mass 2m, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is: [NEET 2019]

A)
$\frac{4}{9}$

B)
$\frac{5}{9}$

C)
$\frac{1}{9}$

D)
$\frac{8}{9}$

• question_answer48) 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 $y=0\text{ }to\text{ }y=1$m is:                [NEET 2019]

A)
25 J

B)
20 J

C)
30 J

D)
5 J

• question_answer49) The energy required to break one bond in DNA is${{10}^{20}}J$. This value in eV is nearly: [NEET 2020]

A)
0.6

B)
0.06

C)
0.006

D)
6