Physics · Class 11 · Work, Energy and Power

Work, Energy and Power for JEE

Everything you need for this topic on one page: the ideas, the formulas, the traps, and free lectures that explain it well.

Last updated: 26 October 2026

Direct answer

Work–energy methods often solve mechanics problems faster than forces.

Work–energy methods often solve mechanics problems faster than forces. This topic also covers potential energy, conservative forces, collisions and power.

Key ideas

Work, Energy and Power: what you must understand

Work–energy theorem: total work = change in kinetic energy
Conservative force: F = −dU/dx; equilibrium where dU/dx = 0
Momentum is conserved in all collisions; kinetic energy only in elastic ones
Coefficient of restitution e = separation speed / approach speed

Formula sheet

Must-know formulas for Work, Energy and Power

W = ∫F·ds, KE = ½mv²
Spring PE = ½kx²
Power P = F·v
1D elastic collision: v₁ = ((m₁−m₂)u₁ + 2m₂u₂)/(m₁+m₂)

One-page formula sheet

Printable Work, Energy and Power formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.

Avoid

Common mistakes students make

Ignoring work by friction or normal force on a moving incline
Using energy conservation when a non-conservative force does work
Wrong sign of work done by gravity

For the exam

How this topic is asked in JEE

Appears frequently. Vertical circle problems combine energy and Newton's second law at the top and bottom. Practise them.

Prerequisites: Laws of Motion and Friction.

NCERT map

Where Work, Energy and Power is in NCERT

Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.

Class	Book	Chapter	Sections JEE asks from
Class 11	Physics Part I	Work, Energy and Power	The work-energy theorem; The concept of potential energy; The conservation of mechanical energy; Power; Collisions

JEE Advanced level

A JEE Advanced-level example on Work, Energy and Power

Question. A block of mass 2 kg is released from rest at the top of a smooth curved track of height 5 m. At the bottom, it undergoes a perfectly elastic collision with another block of mass 3 kg attached to a horizontal spring (k = 500 N/m). The horizontal surface has coefficient of friction μ = 0.2. Find the maximum compression of the spring. (g = 10 m/s²)

Show solution

Use energy conservation for the 2 kg block sliding down: v₁ = √(2gh) = √(2 × 10 × 5) = 10 m/s
Apply elastic collision formula for velocity of 3 kg block: v₂' = (2m₁/(m₁ + m₂)) × v₁ = (4/5) × 10 = 8 m/s
At maximum compression, apply work-energy theorem: (1/2)m₂v₂'² = μm₂gx + (1/2)kx²
Substitute values: (1/2)(3)(64) = (0.2)(3)(10)x + (1/2)(500)x² gives 96 = 6x + 250x²
Solve quadratic 250x² + 6x − 96 = 0 using formula: x = (−6 + √96036)/500 ≈ 0.61 m

Answer: Maximum compression of spring = 0.61 m (or 61 cm)

This example was solved twice independently and both solutions agree.

Free lectures

Best free lectures for Work, Energy and Power

Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.

WORK, ENERGY & POWER in One Shot: All Concepts & PYQs Covered | JEE Main & Advanced — JEE Wallah, 6:43:10
Jump to a subtopic (22)
- 00:00 Introduction
- 03:50 Topics to be covered
- 05:58 Work
- 35:50 Work done by Constant Force
- 52:45 Work done by Variable Force
- 56:08 Questions
- 01:50:40 Work Energy Theorem
- 02:04:40 Questions
- 03:28:15 Break
- 03:52:10 Questions
- 04:07:05 Vertical Circular Motion
- 04:12:00 Questions (Concept)
- 04:55:15 Power
- 05:01:50 Questions
- 05:19:00 Break
- 05:31:55 Conservative and Non-Conservative Force
- 05:43:45 Potential Energy
- 05:53:20 Relation between Conservative Force & Potential Energy
- 06:07:40 Types of Equilibrium
- 06:21:42 Mechanical Energy Conservation
- 06:25:15 Questions
- 06:39:15 Thank you
Work Energy Theorem | Concepts & PYQs | Work Energy Power | JEE Physics | IIT JEE — Eduniti - Physics by Mohit Goenka_IITKGP, 34:16
Jump to a subtopic (11)
- 00:00 Introduction
- 00:27 Must Follow Series Links
- 01:22 Understanding of Work Energy Theorem & Equation
- 07:29 Work done by N & T is zero Cases
- 09:44 How to Write Change in P.E.
- 11:54 Questions 1 (JEE 2019)
- 16:04 Questions 2 (JEE 2020)
- 18:55 Questions 3 (JEE 2020)
- 23:01 Questions 4 (IIT JEE 2011)
- 25:42 Questions 5 (IIT JEE 2014)
- 29:07 Questions 6 (HCV Q43)

Practise

Where to practise for free

6 JEE Main 2026 PYQs on Work, Energy and Power, with solutions.
Read the chapter in NCERT textbooks (official, free), then solve its NCERT Exemplar (official, free) questions.
Chapter-wise past questions: JEE Main and Advanced PYQs and question bank.
Timed practice tests: NTA Abhyas practice tests (official, free) and our free mock tests.
See it move: interactive simulation.

FAQs

Frequently asked questions

Is Work, Energy and Power important for JEE Main 2027?

Appears frequently. It is part of the official 'Work, Energy and Power' unit in the JEE Main 2027 syllabus.

What are the most important formulas in Work, Energy and Power?

W = ∫F·ds, KE = ½mv²; Spring PE = ½kx²; Power P = F·v.

How should I study Work, Energy and Power for JEE?

Understand the key ideas from NCERT or one full lecture, learn the formula sheet, then solve 25–30 past JEE questions on the topic. Vertical circle problems combine energy and Newton's second law at the top and bottom. Practise them.