What are JEE Laws of Motion questions?

JEE Laws of Motion questions test Newton's laws of motion, free-body diagrams, friction, tension, circular motion basics, and connected-body dynamics. These concepts are regularly asked in both JEE Main and JEE Advanced.

Is Laws of Motion important for JEE Main 2026?

Yes. Laws of Motion is a high-weightage chapter for JEE Main 2026, contributing around 2–3 questions on average and serving as the foundation for the entire Mechanics syllabus.

Which Laws of Motion topics are most important for JEE?

Free-body diagrams, friction, pulley systems, inclined plane problems, tension calculations, and pseudo-force concepts are among the most frequently tested topics in JEE.

Is Laws of Motion difficult for JEE?

Laws of Motion is considered moderately difficult because it requires strong conceptual understanding and the ability to analyse multiple forces acting simultaneously on a body.

How many Laws of Motion questions come in JEE Advanced?

JEE Advanced typically includes 2–3 questions from Laws of Motion, often involving pulleys, connected bodies, friction, inclined planes, and non-inertial frames.

How can I prepare Laws of Motion for JEE Main and Advanced?

To master Laws of Motion, practise drawing free-body diagrams, solve topic-wise previous year JEE questions, learn friction concepts thoroughly, and attempt timed mock tests regularly.

What are the most common mistakes in JEE Laws of Motion questions?

Students often include non-existent forces, choose the wrong friction direction, draw incorrect free-body diagrams, or forget constraint relations in connected-body systems.

Which formulas are important in Laws of Motion for JEE?

Key formulas include Newton's second law, friction equations, tension relations, pseudo-force formulas, and equations used for analysing connected bodies and inclined plane systems.

JEE Laws of Motion Questions

Laws of Motion is the heart of Mechanics and one of the most frequently tested chapters in JEE Physics. Built on Newton's three laws, it governs how forces produce motion and is the foundation for dynamics, circular motion, and rotational mechanics. Because nearly every mechanics problem reduces to a free-body analysis, JEE Laws of Motion questions are essential practice for both JEE Main and JEE Advanced. This chapter covers force analysis, friction, tension, pseudo forces, and the dynamics of connected systems. JEE Main tests direct applications of Newton's laws and friction, while JEE Advanced layers in pulleys, inclined planes, and non-inertial frames for higher-order reasoning. Practising topic-wise JEE Questions trains you to draw accurate free-body diagrams, the single most important skill in this chapter.

Download JEE Laws of Motion PDF

Question 1 JEE Mains

A uniform chain of length $$l\ $$ has one of its end attached to the wall a point A, while $$\frac{3l}{4}$$of the length of the chain is lying on table as shown in figure. Find the minimum co-efficient of friction between table and chain so that chain remains in equilibrium is.

$$\frac{1}{2}$$

$$\frac{1}{4}$$

$$\frac{3}{4}$$

$$\frac{4}{3}$$

Solution

Let the mass per unit length of the chain be $$\lambda$$.

The length of the inclined part is  $$l_i=\frac{l}{4}$$

Hence, its weight is  $$W_i=\lambda\frac{l}{4}g$$

Let the tension at the junction of the inclined and horizontal parts be $$T$$.

For the inclined part, the tension at the junction is horizontal. The tension at A makes an angle $$37^\circ$$ with the vertical.

For equilibrium of the inclined part,  $$T_A\cos37^\circ=W_i$$

Therefore,  $$T_A=\frac{W_i}{\cos37^\circ}$$

The horizontal component of this tension is balanced by $$T$$:  $$T=T_A\sin37^\circ$$

Hence,  $$T=W_i\tan37^\circ$$

Using  $$\tan37^\circ=\frac{3}{4}$$

we get  $$T=\lambda\frac{l}{4}g\times\frac{3}{4}$$

$$T=\frac{3\lambda lg}{16}$$

Now, the length of the chain lying on the table is  $$l_t=\frac{3l}{4}$$

Therefore, the normal reaction is  $$N=\lambda\frac{3l}{4}g$$

For limiting equilibrium,  $$f=\mu N$$

The friction balances the tension $$T$$:  $$\mu N=T$$

Therefore,  $$\mu=\frac{T}{N}$$

$$\mu=\frac{\frac{3\lambda lg}{16}}{\frac{3\lambda lg}{4}}$$

$$\mu=\frac{1}{4}$$

Therefore,  $${\mu_{\min}=\frac14}$$

Hence, the correct option is B.

Laws of Motion Topic Overview

Parameter	Details
Topic Name	Laws of Motion
Subject	Physics
JEE Main Weightage	~4–6% (2–3 questions on average)
JEE Advanced Weightage	~6–8% (often in multi-body problems)
Difficulty Level	Moderate to High
Important Concepts	Newton's Laws, Free-Body Diagrams, Friction, Tension, Pseudo Forces
Recommended Practice Level	High – attempt 70+ mixed problems

Why Practice JEE Laws of Motion Questions?

High weightage: Laws of Motion contributes 2–3 questions in JEE Main most years.
Core of mechanics: Free-body analysis here is reused across circular and rotational motion.
Strong in Advanced: Connected systems and pseudo-force problems are JEE Advanced favourites.
Builds analytical discipline: Drawing correct free-body diagrams trains systematic problem-solving.
Friction is universal: Friction concepts appear in many other mechanics chapters.
Improves accuracy: Practice reduces the sign and force-direction errors common here.
Rewards method over memory: A consistent approach beats formula memorisation in this chapter.

Important Concepts and Subtopics

Concept	Importance	Difficulty Level	Frequently Asked In
Newton's Three Laws	Very High	Easy–Moderate	JEE Main & Advanced
Free-Body Diagrams	Very High	Moderate	JEE Main & Advanced
Friction (Static & Kinetic)	Very High	Moderate	JEE Main & Advanced
Tension & Connected Bodies	High	Moderate–High	JEE Main & Advanced
Pulley Systems	High	High	JEE Advanced
Pseudo Forces & Non-Inertial Frames	Moderate	High	JEE Advanced
Circular Motion Dynamics	High	Moderate–High	JEE Main & Advanced

Preparation Strategy for JEE Laws of Motion

Concept learning: Master Newton's three laws and the concept of net force. The key skill is drawing a correct free-body diagram for each object, marking every real force acting on it.

Formula revision: Keep friction relations, tension-balance conditions, and circular-motion force equations ready. Pairing practice with structured JEE Online Coaching helps you internalise the systematic free-body approach and clear doubts on tricky pulley and pseudo-force problems.

Problem-solving techniques: For connected systems, isolate each body, write its equation, and use the constraint relations to link accelerations. For non-inertial frames, add the pseudo force before analysing.

Common mistakes: Adding forces that don't act on the chosen body, ignoring friction direction, confusing static and kinetic friction limits, and forgetting constraint relations in pulley problems.

Exam strategy: Start with single-body and friction questions, then move to connected systems and pseudo-force problems that require more setup.

JEE Main & Advanced Weightage Analysis

Exam	Average Questions	Expected Marks
JEE Main	2–3	8–12
JEE Advanced	2–3 (often multi-body)	8–14

Laws of Motion is a consistently heavy chapter in JEE Main and a recurring source of multi-body problems in JEE Advanced. Mastery here directly improves performance across the entire Mechanics unit.

Tips to Solve Laws of Motion Questions Faster

Draw a clean free-body diagram for every object before writing any equation.
Mark only real forces, never include "ma" as a force in an inertial frame.
For connected bodies, write the constraint relation early to link their accelerations.
Check whether friction is static or kinetic before applying its formula.
In non-inertial frames, add the pseudo force opposite to the frame's acceleration.
Resolve forces along and perpendicular to the direction of motion for cleaner equations.

Practising these under timed conditions with a JEE Mock Test helps convert the free-body method into fast, reliable instinct.

JEE Laws of Motion Questions

Laws of Motion Topic Overview

Why Practice JEE Laws of Motion Questions?

Important Concepts and Subtopics

Preparation Strategy for JEE Laws of Motion

JEE Main & Advanced Weightage Analysis

Tips to Solve Laws of Motion Questions Faster

Frequently Asked Questions

Download resources

JEE Laws of Motion Questions

Laws of Motion Topic Overview

Why Practice JEE Laws of Motion Questions?

Important Concepts and Subtopics

Preparation Strategy for JEE Laws of Motion

JEE Main & Advanced Weightage Analysis

Tips to Solve Laws of Motion Questions Faster

Frequently Asked Questions

Download resources

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