Introduction to Laws of Motion

The Laws of Motion are fundamental principles that describe the relationship between the motion of an object and the forces acting on it. These laws, formulated by Sir Isaac Newton, are central to mechanics and form a major part of NEET Physics syllabus.

StudentBro provides comprehensive notes with clear explanations, examples, and problem-solving techniques, enabling NEET aspirants to master this crucial chapter.

Direct Links to Download 2025-26 Physics Notes (PDF)

► Click “Download Here” next to your subject to access the free PDF.

Newton’s First Law of Motion

Also called the Law of Inertia, it states:

• “An object remains at rest or continues to move in a straight line with uniform speed unless acted upon by an external force.”

Key points for NEET:

• Inertia is the resistance of an object to change its state of motion

• Mass is a measure of inertia

• Applications: Motion of vehicles, satellite motion

Understanding inertia helps students solve conceptual NEET questions on forces and motion.

Newton’s Second Law of Motion

This law establishes the relationship between force, mass, and acceleration:

• F = ma (Force = mass × acceleration)

• The acceleration of an object is directly proportional to the net force and inversely proportional to its mass

Key points for NEET:

• Force and acceleration are vectors

• It is applicable to linear and two-dimensional motion

• Basis for solving numerical problems on force, acceleration, and mass

StudentBro notes explain derivation and applications step-by-step for NEET clarity.

Newton’s Third Law of Motion

Also known as the Action-Reaction Law:

• “For every action, there is an equal and opposite reaction.”

Key points for NEET:

• Forces always act in pairs

• Action and reaction act on different bodies, not the same body

• Applications: Walking, rocket propulsion, swimming

Understanding this law is essential for solving dynamics and force-based NEET problems.

Force

Force is an interaction that changes or tends to change the motion of an object. Types of forces include:

• Gravitational Force: Attraction between masses

• Frictional Force: Opposes relative motion between surfaces

• Tension Force: Force transmitted through a string or rope

• Normal Force: Perpendicular force from a surface

StudentBro notes provide examples and conceptual clarity for NEET aspirants.

Friction

Friction is a force that opposes motion. Key points include:

• Types: Static friction, kinetic friction, rolling friction

• Laws of friction: Friction is proportional to normal force, independent of contact area

• NEET often includes numerical and conceptual questions on friction

Understanding friction is essential for solving motion problems on inclined planes and moving objects.

Inertia

Inertia is a fundamental concept related to Newton’s First Law:

• Inertia of Rest: Resistance to start moving from rest

• Inertia of Motion: Resistance to change in motion

• Inertia of Direction: Resistance to change in direction of motion

Mass is the measure of inertia, and NEET questions often involve conceptual understanding and numerical applications.

Momentum

Momentum is the product of mass and velocity: p = mv

• Newton’s Second Law in terms of momentum: F = dp/dt

• Law of conservation of momentum: Total momentum of an isolated system remains constant

Applications for NEET: Collisions (elastic and inelastic), recoil of guns, explosions.

Equilibrium of Forces

An object is in equilibrium if net force and net torque acting on it are zero:

• Translational Equilibrium: Net force = 0

• Rotational Equilibrium: Net torque = 0

NEET often tests problems on forces in equilibrium, requiring understanding of tension, normal, and friction forces.

Circular Motion and Centripetal Force

Objects moving in a circular path experience:

• Centripetal Acceleration: a_c = v²/r

• Centripetal Force: Force required to keep an object in circular motion

• Applications: Motion of planets, cars on curves, satellites

StudentBro notes cover circular motion with clear examples and NEET-focused numerical techniques.

Free Body Diagrams (FBD)

FBDs are essential for solving NEET problems:

• Represent all forces acting on an object

• Include weight, normal, friction, tension, and applied forces

• Help in calculating acceleration, net force, and tension in strings

Understanding FBDs simplifies complex mechanics questions.

Applications of Laws of Motion in NEET

Laws of motion are applied in:

• Motion on inclined planes

• Pulley systems and connected bodies

• Collisions and momentum problems

• Motion under friction and external forces

Mastery of this chapter is critical for scoring high in NEET Physics.

Tips for NEET Preparation on Laws of Motion

1. Understand the conceptual meaning of all three Newton’s laws.

2. Practice problems involving force, acceleration, and mass.

3. Draw free body diagrams for every numerical problem.

4. Memorize formulas for friction, centripetal force, and momentum.

5. Solve previous NEET questions to identify common patterns.

StudentBro notes are designed to help aspirants implement these tips effectively.

Advantages of StudentBro NEET Physics Notes

• Covers Newton’s laws, force, friction, inertia, and momentum in detail

• Includes practical examples and numerical techniques

• Structured for easy revision and clear conceptual understanding

• Focused on NEET syllabus and high-yield topics

These notes ensure aspirants can tackle laws of motion questions confidently and efficiently.

Conclusion

The chapter Laws of Motion is a cornerstone of NEET Physics. Mastery of Newton’s laws, force, friction, momentum, and related concepts is essential for solving both conceptual and numerical problems.

StudentBro NEET Physics notes provide structured, clear, and exam-focused guidance, enabling aspirants to confidently solve problems in laws of motion and excel in NEET exams.