NEET PhysicsUpdated 19 Oct 2026

Work, Energy and Power: NEET PYQs and weightage

Work, Energy and Power carries 3.6 of 100 Physics marks in NEET by past-paper share: 27 of the 758 tagged NEET Physics PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 12 of 30 Physics chapters.

Take the 25-question Work, Energy and Power test Formula sheet ↓All NEET Physics chapters

3.6/100 Weight in Physics

Exam importance (3/5, by past-paper share)

27 NEET PYQs

512 Practice questions

478 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Physics PYQs in the bank (27 of 758), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

Work, Energy and Power: formula sheet for NEET

14 formulas, each with when to use it. Copy it onto one page of your notebook: that page is this chapter's handbook.

Work by a constant force
$W = F \cdot d = F d cos θ = F_{x} d_{x} + F_{y} d_{y} + F_{z} d_{z}$
Use it when: the force stays constant over the displacement; $θ$ is the angle between $F$ and $d$ ( $θ > 9 0^{\circ}$ gives negative work, $θ = 9 0^{\circ}$ gives zero)
Work-energy theorem
$K_{f} - K_{i} = W_{net}$
Use it when: speeds are asked but time is not; add the work of every force acting, friction included
Kinetic energy
$K = \frac{1}{2} m v^{2}$
Use it when: finding speed from energy; $K$ is never negative
Work by a variable force
$W = \int_{x_{i}}^{x_{f}} F (x) d x = area under the F - x graph$
Use it when: $F$ changes with position or an $F$ – $x$ graph is given (area below the $x$ -axis counts as negative)
Conservation of mechanical energy
$K_{i} + V_{i} = K_{f} + V_{f}$
Use it when: only conservative forces (gravity, spring) do work
With non-conservative forces
$E_{f} - E_{i} = W_{nc}$
Use it when: friction or air resistance acts; $W_{nc}$ is usually negative and depends on the path
Gravitational PE
$V = m g h$
$v = 2 g h (released from rest, after falling h)$
$v = 2 g (H - h) (at height h after release from H)$
Use it when: $h$ is small compared with the Earth's radius; the speed at the bottom of a smooth incline of height $h$ is also $2 g h$ , whatever the angle
Force from potential energy
$F (x) = - \frac{d V}{d x}$
Use it when: $V (x)$ is given and the force is needed; a conservative force does zero work over a closed path
Spring
$F_{s} = - k x$
$V = \frac{1}{2} k x^{2} (k in N m^{- 1})$
Use it when: $x$ is the stretch or compression measured from the natural length
Work by a spring force
$W_{s} = \frac{1}{2} k x_{i}^{2} - \frac{1}{2} k x_{f}^{2}$
Use it when: the block moves from $x_{i}$ to $x_{f}$ ; it is negative while the spring is being stretched or compressed further
Block on a spring
$\frac{1}{2} k x_{m}^{2} = \frac{1}{2} k x^{2} + \frac{1}{2} m v^{2}$
$v_{m a x} = x_{m} \frac{k}{m} (at x = 0)$
Use it when: a block oscillates on a smooth surface; for maximum compression by a moving body, set $\frac{1}{2} m v^{2} = \frac{1}{2} k x_{m}^{2}$ (add $μ m g x_{m}$ on the right if there is friction)
Power
$P_{av} = \frac{W}{t}$
$P = \frac{d W}{d t} = F \cdot v (1 hp = 746 W; 1 kWh = 3.6 \times 1 0^{6} J)$
Use it when: a motor, pump or lift runs at constant speed; for a lift, $P = (m g + friction) \times v$
1-D elastic collision with m2 at rest
$v_{1 f} = \frac{( m _{1} - m _{2} ) v _{1 i}}{m _{1} + m _{2}}$
$v_{2 f} = \frac{2 m _{1} v _{1 i}}{m _{1} + m _{2}}$
Use it when: a head-on collision conserves both momentum and KE; equal masses exchange velocities, and fraction of KE transferred $= \frac{4 m _{1} m _{2}}{( m _{1} + m _{2} ) ^{2}}$
Completely inelastic collision (m2 at rest)
$v_{f} = \frac{m _{1} v _{1 i}}{m _{1} + m _{2}}$
$KE lost = \frac{1}{2} \frac{m _{1} m _{2} v _{1 i}^{2}}{m _{1} + m _{2}}$
Use it when: the bodies stick together; momentum is conserved and KE is not

Trap

Using K_i + V_i = K_f + V_f when friction is present. Once friction or any non-conservative force does work, switch to W_net = ΔK or E_f − E_i = W_nc, and count friction's work as negative.

How does NEET ask Work, Energy and Power?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1PhysicsNEET UG PYQWork Energy Theorem

Try right here · No sign-in

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

\frac{F _{A}}{F _{B}}

Answer key (D) & worked solution

Correct answer: Option D

W = Δ K E

- F s = 0 - K E

F s = K E

F_{1} = \frac{100}{1000} = \frac{1}{10}, F_{2} = \frac{225}{1500} = \frac{15}{100}

\frac{F _{1}}{F _{2}} = \frac{1}{10} \times \frac{100}{15} = \frac{10}{15} = \frac{2}{3}

Q2PhysicsNEET UG PYQPower

A particle of mass m is driven by a machine that delivers constant power k watt. If the particle starts from rest the force on the particle at time t is:

\frac{1}{2} mk t^{- 1/2}

mk t^{- 1/2}

\frac{mk}{2} t^{- 1/2}

2 mk t^{- 1/2}

Answer key (C) & worked solution

Correct answer: Option C

k = F v = m \times \frac{d v}{d t} \times v

\Rightarrow \int v d v = \int \frac{k}{m} d t

\Rightarrow v = \frac{2 k t}{m}

\Rightarrow \frac{d v}{d t} = \frac{k}{2 m t}

Now, Force

= m \frac{d v}{d t} = \frac{mk}{2 t}

Q3PhysicsNEET UG PYQPower

Water falls from a height of 60 m 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/s

^{2}

)

A12 .3 kW

B7.0 kW

C10.2 kW

D8.1 kW

Answer key (D) & worked solution

Correct answer: Option D

_{i}

= (15) (10) (60) = 9000 W P

_{l oss}

= (10/100) x 9000 = 900 W P = 8100 W = 8.1 kW

Q4PhysicsNEET UG PYQPower

At any instant of time t, the displacement of any particle is given by 2t - 1 (SI unit) under the influence of force of 5N. The value of instantaneous power is (in SI unit):

D10

Answer key (D) & worked solution

Correct answer: Option D

x = 2 t - 1

\frac{d x}{d t} = v = 2

P = F v cos θ

= 5 \times 2 = 10 W

Q5PhysicsNEET UG PYQWork Done by Constant and Variable Force

A particle of mass

M

moves along a horizontal

x

axis from

x = 0

x = L

. The coefficient of kinetic friction varies as a function of

x

μ_{k} (x) = μ_{0} - α x

, where

μ_{0}, α

are constants of appropriate dimensions, so that

μ_{k} (L) = 0

. The total work done by the frictional force during the motion is

n μ_{0} M g L

, where

g

is the acceleration due to gravity. The value of

n

is:

\frac{1}{3}

\frac{1}{2}

Answer key (C) & worked solution

Correct answer: Option C

Given

μ_{k} (x) = μ_{0} - α x

and

μ_{k} (L) = 0 = μ_{0} - α L \Rightarrow μ_{0} = α L

Magnitude of work done by frictional force,

W_{f} = \int d W_{f}

where

d W_{f} = f_{k} d x = μ_{k} N d x = μ_{k} M g d x = (μ_{0} - α x) M g d x

∴ W_{f} = \int_{0}^{L} μ_{0} M g d x - \int_{0}^{L} α M g x d x = μ_{0} M g [x]_{0}^{L} - α M g [\frac{x ^{2}}{2}]_{0}^{L}

\Rightarrow n μ_{0} M g L = μ_{0} M g L - (\frac{μ _{0}}{L}) M g (\frac{L ^{2}}{2}) = \frac{μ _{0} M g L}{2}

\Rightarrow n = \frac{1}{2}

Q6PhysicsNEET UG PYQCollisions

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

A0.8

B0.25

C0.5

D0.4

Answer key (B) & worked solution

Correct answer: Option B

According to law of conservation of linear momentum,

m v + 4 m \times 0 = 4 m v^{'} + 0

v^{'} = \frac{v}{4}

e = \frac{Relative velocity of separation}{Relative velocity of approach} = \frac{\frac{v}{4}}{v}

e = \frac{1}{4} = 0.25

Q7PhysicsNEET UG PYQWork Done by Constant and Variable Force

A force

F = (5 \hat{i} + 3 \hat{j} + 2 \hat{k}) N

is applied over a particle which displaces it from its origin to the point

r = (2 \hat{i} - \hat{j}) m

.The work done on the particle in Joule is

A-7

B+7

C+10

D+13

Answer key (B) & worked solution

Correct answer: Option B

Work done in displacing the particle

W = F . r

= (5 \hat{i} + 3 \hat{j} + 2 \hat{k}) . (2 \hat{i} - \hat{j})

= 2 + 3 \times (- 1) + 2 \times 0 = 10 - 3 = 7 J

Q8PhysicsNEET UG PYQWork Done by Constant and Variable Force

Consider a drop of rain water having mass 1g 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) 100 J (ii) 8.75 J

B(i) 10 J (ii) –8.75 J

C(i) –10 J (ii) –8.25 J

D(i) 1.25 J (ii) –8.25 J

Answer key (B) & worked solution

Correct answer: Option B

Work done by the gravity

(W_{g}) = m g h

1 0^{- 3} \times 10 \times 1 0^{3} = 10 J

By work-energy theorem

= W_{g} + W_{r es} = Δ K E

10 + W_{r es} = \frac{1}{2} \times 1 0^{3} \times (50)^{2}

W_{r es} = - 8.75 J

Which topics in Work, Energy and Power carry the most questions?

All 9 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

Topic	PYQs	Practice questions
Work Done by Constant and Variable Force	7	96
Collisions	6	103
Power	6	65
Vertical Circular Motion	4	56
Work Energy Theorem	2	59
Spring Block System	2	34
The Concept of Potential Energy	0	60
Kinetic Energy	0	36
Miscellaneous Examples	0	3

Why does Work, Energy and Power show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in Work, Energy and Power, ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

How ViJEEta scores you

What happens when you test Work, Energy and Power?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

Start the Work, Energy and Power test

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Work, Energy and Power: NEET PYQs and weightage

Work, Energy and Power: formula sheet for NEET

Work by a constant force

Work-energy theorem

Kinetic energy

Work by a variable force

Conservation of mechanical energy

With non-conservative forces

Gravitational PE

Force from potential energy

Spring

Work by a spring force

Block on a spring

Power

1-D elastic collision with m2 at rest

Completely inelastic collision (m2 at rest)

How does NEET ask Work, Energy and Power?

Which topics in Work, Energy and Power carry the most questions?

Why does Work, Energy and Power show "–" until you answer 3 questions?

What happens when you test Work, Energy and Power?

Chapters either side of Work, Energy and Power by weight