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OpenNewton's laws connect force and motion.
Newton's laws connect force and motion. JEE questions use free-body diagrams, pulleys, connected blocks, friction and circular motion dynamics.
Physics · Class 11 · Laws of Motion
Laws of Motion and Friction 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
Key ideas
Laws of Motion and Friction: what you must understand
- Draw a free-body diagram for each body before writing equations
- Static friction adjusts up to μₛN; kinetic friction is μₖN
- Pseudo force −ma acts in a non-inertial frame
- In circular motion the net force towards the centre is mv²/r
Formula sheet
Must-know formulas for Laws of Motion and Friction
- F_net = ma = dp/dt
- f_s ≤ μₛN, f_k = μₖN
- Banked road (no friction): tanθ = v² / rg
- Impulse J = FΔt = Δp
Print
One-page formula sheet
Printable Laws of Motion and Friction formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.
Avoid
Common mistakes students make
- Assuming friction always equals μN
- Forgetting the normal force changes on an incline or with an applied angled force
- Treating centripetal force as an extra force on the FBD
For the exam
How this topic is asked in JEE
Appears frequently. Connected-body and friction questions are standard. Always check first whether the block moves at all.
Prerequisites: Kinematics (Motion in 1D and 2D).
NCERT map
Where Laws of Motion and Friction 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 | Laws of Motion | Newton's First Law of Motion; Newton's Second Law of Motion; Newton's Third Law of Motion; Conservation of Momentum; Friction |
JEE Advanced level
A JEE Advanced-level example on Laws of Motion and Friction
Question. A block A of mass 4 kg rests on a rough horizontal table with coefficient of friction μ = 0.25. It is connected by a light inextensible string passing over a smooth pulley at the edge of the table to another block B of mass 6 kg hanging freely. The system is released from rest. Find the acceleration of the system and the tension in the string. (Take g = 10 m/s²)
Show solution
- Draw free body diagrams: Block A has tension T pulling it forward and friction f = μm_A g = 0.25 × 4 × 10 = 10 N opposing motion. Block B has weight 60 N downward and tension T upward.
- For block A (horizontal motion): T − f = m_A × a, so T − 10 = 4a
- For block B (vertical motion, taking downward positive): m_B g − T = m_B × a, so 60 − T = 6a
- Add both equations: (T − 10) + (60 − T) = 4a + 6a gives 50 = 10a, so a = 5 m/s²
- Substitute back: T = 10 + 4 × 5 = 30 N
Answer: Acceleration = 5 m/s², Tension = 30 N
This example was solved twice independently and both solutions agree.
Free lectures
Best free lectures for Laws of Motion and Friction
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.
- LAWS OF MOTION in One Shot: All Concepts & PYQs Covered | JEE Main & Advanced — JEE Wallah, 7:48:33
Jump to a subtopic (18)
- 00:00 Introduction
- 06:55 Inertia
- 30:38 Tension Force
- 56:33 Equilibrium
- 01:28:16 Lami's Theorem
- 01:41:22 Pulley System
- 02:35:28 Concept (Questions)
- 03:16:05 Ideal Spring
- 03:36:50 Psuedo Force
- 04:27:10 Constraint Motion (Questions)
- 04:56:40 Questions
- 05:36:10 Friction
- 06:08:35 Questions
- 06:48:40 Angle of Repose
- 06:52:48 Angle of Friction
- 06:59:04 Questions
- 07:27:36 Spring Cutting
- 07:46:00 Thank you
- Newton's Laws of Motion | Complete REVISION for JEE Physics | Mohit Sir (IITKGP) — Eduniti - Physics by Mohit Goenka_IITKGP, 49:47
Jump to a subtopic (15)
- 00:00 Introduction
- 00:15 Topics to be discussed
- 01:09 All links for Revision series
- 02:30 Common Forces Acting on Body
- 07:01 Static Equilibrium (Lami's Theorem)
- 13:29 Pulley Block System
- 23:28 Weighing Machine Concept
- 27:02 Spring Balance Concept
- 29:27 Spring Cut & Combination Concept
- 31:13 FBD - Most Important Point
- 34:56 Pseudo Force Concept
- 37:46 Numerical on Pseudo Force
- 45:17 Variable Force
- 48:24 Important Links for NLM
- 48:48 PYQs Links
Practise
Where to practise for free
- 11 JEE Main 2026 PYQs on Laws of Motion and Friction, 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 Laws of Motion and Friction important for JEE Main 2027?
Appears frequently. It is part of the official 'Laws of Motion' unit in the JEE Main 2027 syllabus.
What are the most important formulas in Laws of Motion and Friction?
F_net = ma = dp/dt; f_s ≤ μₛN, f_k = μₖN; Banked road (no friction): tanθ = v² / rg.
How should I study Laws of Motion and Friction 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. Connected-body and friction questions are standard. Always check first whether the block moves at all.