Chapter 6 - How Forces Affect Motion

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CBSE Class 9 Science Chapter 6 : How forces affect motion Notes

Important concepts, key explanations, and useful details help students study each chapter in a clear and organised way. CBSE Notes for Class 9 Science bring these points together, making it easier to follow the syllabus, strengthen subject knowledge, and revise important topics. Chapter 6, “How Forces Affect Motion ”, explains the relationship between force and the movement of objects. It covers balanced and unbalanced forces, inertia, momentum, Newton’s laws of motion, and their applications, helping students understand how forces change the state of motion and affect objects in everyday situations.

1.0Download CBSE Notes in Class 9 Science How forces affect motion

Download CBSE Class 9 Science Chapter 6: How Forces Affect Motion Notes to understand the concepts of force, motion, and their effects in a simple format.

NCERT Solutions Class 9 Science Chapter 6 Notes

2.0Important Concepts of Class 9 Science Chapter 6 :How forces affect motion

Introduction to Force

Force as a push or pull
Contact and non-contact forces
Force as a vector quantity
Effects of force on objects

Balanced and Unbalanced Forces

Balanced forces
Unbalanced forces
Net force (Resultant force)
Equilibrium of an object
Effect of balanced and unbalanced forces on motion

Galileo's Ideas on Motion

Galileo's inclined plane experiment
Motion on a frictionless surface
Concept leading to inertia

Newton's First Law of Motion

Statement of the first law
Law of inertia
Conditions for an object to remain at rest or in uniform motion

Inertia

Inertia of rest
Inertia of motion
Inertia of direction
Relation between mass and inertia

Linear Momentum

Definition of momentum
Momentum formula
SI unit of momentum
Factors affecting momentum

Newton's Second Law of Motion

Statement of the second law
Rate of change of momentum
Mathematical expression
Derivation of F = ma
SI unit of force (Newton)

Newton's Third Law of Motion

Statement of the third law
Action and reaction forces
Characteristics of action-reaction pairs
Real-life applications

Law of Conservation of Momentum

Statement of the law
Isolated system
Proof using two-body collision
Applications such as recoil of a gun and rocket propulsion

Important Formulae

Quantity	Formula
Momentum	p = mv
Newton's Second Law	F = Δp/t
Force	F = ma
Acceleration	a = (v − u)/t
Conservation of Momentum	m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

Important Table: Balanced vs Unbalanced Forces

Balanced Forces	Unbalanced Forces
Net force = 0	Net force ≠ 0
No acceleration	Produces acceleration
Object remains at rest or moves with uniform velocity	Changes the state of rest or uniform motion
Velocity remains constant	Velocity changes

Important Table: Types of Inertia

Type	Meaning
Inertia of Rest	Tendency to remain at rest
Inertia of Motion	Tendency to continue uniform motion
Inertia of Direction	Tendency to continue moving in the same direction

3.0Other Study Materials for Class 9 Science

Students can use additional study materials along with these notes, such as:

Class 9 Science NCERT textbook

Class 9 Science NCERT Solutions

Class 9 Science Syllabus

Class 9 Science Sample Papers

4.0 Why CBSE Notes for Class 9 Science Chapter 6: How Forces Affect Motion

Understand the Role of Force: These notes help students learn how force can change the state of rest or motion of an object and influence its movement.
Learn Balanced and Unbalanced Forces: The notes explain how balanced and unbalanced forces affect objects and determine whether their motion changes.
Understand Inertia and Its Applications: Students can revise the concept of inertia, its types, and examples related to everyday experiences.
Master Newton’s Laws of Motion: These notes simplify Newton’s three laws of motion along with their explanations and real-life applications.
Learn Momentum and Force Relationship: The chapter notes explain momentum and how force is related to the change in motion of objects.
Support Better Problem Solving: Important concepts, formulas, and examples from the chapter are organised to help students apply force and motion principles effectively.

Chapter-wise CBSE Notes for Class 9 Science:

Class 9 Science Chapter 1 - Exploration: Entering the world of secondary science Notes

Class 9 Science Chapter 2 - Cell:The building blocks of life Notes

Class 9 Science Chapter 3 - Tissues in action Notes

Class 9 Science Chapter 4 - Describing motion around us Notes

Class 9 Science Chapter 5 -Exploring mixtures and their separation Notes

Class 9 Science Chapter 6 - How forces affect motion Notes

Class 9 Science Chapter 7 - Work,Energy and simple machines Notes

Class 9 Science Chapter 8 - Journey inside the atom Notes

Class 9 Science Chapter 9 - Atomic foundations of Matter Notes

Class 9 Science Chapter 10 - Sound Waves:Characteristics Applications Notes

Class 9 Science Chapter 11 - Reproduction:How Life Continues Notes

Class 9 Science Chapter 12 - Patterns in life:Diversity and Classification Notes

Class 9 Science Chapter 13 - Earth as a system:Energy,Matter and Life Notes

Chapter-wise NCERT Solutions for Class 9 Science:

Chapter 1 - Exploration: Entering the world of secondary science

Chapter 2 - Cell: The building blocks of life

Chapter 3 - Tissues in action

Chapter 4 - Describing motion around us

Chapter 5 - Exploring mixtures and their separation

Chapter 6 - How forces affect motion

Chapter 7 - Work,Energy and simple machines

Chapter 8 - Journey inside the atom

Chapter 9- Atomic foundations of Matter

Chapter 10- Sound Waves: Characteristics Applications

Chapter 11- Reproduction:How Life Continues

Chapter 12 - Patterns in life:Diversity andClassification

Chapter 13 - Earth as a system:Energy,Matter and Life

Frequently Asked Questions

Join ALLEN!

(Session 2026 - 27)

Name

Mobile Number

Class

Choose class

Goal

Choose your goal

Preferred Programs

Preferred Mode

State

Choose State

I agree to

I authorise ALLEN Career Institute Pvt Ltd to send me regular updates via Phone calls, Whatsapp, SMS, Robocalls (Automated Calls), Emails, or on postal address.

CBSE Class 9 Science Chapter 6 : How forces affect motion Notes

Important concepts, key explanations, and useful details help students study each chapter in a clear and organised way. CBSE Notes for Class 9 Science bring these points together, making it easier to follow the syllabus, strengthen subject knowledge, and revise important topics. Chapter 6, “How Forces Affect Motion ”, explains the relationship between force and the movement of objects. It covers balanced and unbalanced forces, inertia, momentum, Newton’s laws of motion, and their applications, helping students understand how forces change the state of motion and affect objects in everyday situations.

1.0Download CBSE Notes in Class 9 Science How forces affect motion

Download CBSE Class 9 Science Chapter 6: How Forces Affect Motion Notes to understand the concepts of force, motion, and their effects in a simple format.

NCERT Solutions Class 9 Science Chapter 6 Notes

2.0Important Concepts of Class 9 Science Chapter 6 :How forces affect motion

Introduction to Force

Force as a push or pull
Contact and non-contact forces
Force as a vector quantity
Effects of force on objects

Balanced and Unbalanced Forces

Balanced forces
Unbalanced forces
Net force (Resultant force)
Equilibrium of an object
Effect of balanced and unbalanced forces on motion

Galileo's Ideas on Motion

Galileo's inclined plane experiment
Motion on a frictionless surface
Concept leading to inertia

Newton's First Law of Motion

Statement of the first law
Law of inertia
Conditions for an object to remain at rest or in uniform motion

Inertia

Inertia of rest
Inertia of motion
Inertia of direction
Relation between mass and inertia

Linear Momentum

Definition of momentum
Momentum formula
SI unit of momentum
Factors affecting momentum

Newton's Second Law of Motion

Statement of the second law
Rate of change of momentum
Mathematical expression
Derivation of F = ma
SI unit of force (Newton)

Newton's Third Law of Motion

Statement of the third law
Action and reaction forces
Characteristics of action-reaction pairs
Real-life applications

Law of Conservation of Momentum

Statement of the law
Isolated system
Proof using two-body collision
Applications such as recoil of a gun and rocket propulsion

Important Formulae

Quantity	Formula
Momentum	p = mv
Newton's Second Law	F = Δp/t
Force	F = ma
Acceleration	a = (v − u)/t
Conservation of Momentum	m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

Important Table: Balanced vs Unbalanced Forces

Balanced Forces	Unbalanced Forces
Net force = 0	Net force ≠ 0
No acceleration	Produces acceleration
Object remains at rest or moves with uniform velocity	Changes the state of rest or uniform motion
Velocity remains constant	Velocity changes

Important Table: Types of Inertia

Type	Meaning
Inertia of Rest	Tendency to remain at rest
Inertia of Motion	Tendency to continue uniform motion
Inertia of Direction	Tendency to continue moving in the same direction

3.0Other Study Materials for Class 9 Science

Students can use additional study materials along with these notes, such as:

Class 9 Science NCERT textbook

Class 9 Science NCERT Solutions

Class 9 Science Syllabus

Class 9 Science Sample Papers

4.0 Why CBSE Notes for Class 9 Science Chapter 6: How Forces Affect Motion

Understand the Role of Force: These notes help students learn how force can change the state of rest or motion of an object and influence its movement.
Learn Balanced and Unbalanced Forces: The notes explain how balanced and unbalanced forces affect objects and determine whether their motion changes.
Understand Inertia and Its Applications: Students can revise the concept of inertia, its types, and examples related to everyday experiences.
Master Newton’s Laws of Motion: These notes simplify Newton’s three laws of motion along with their explanations and real-life applications.
Learn Momentum and Force Relationship: The chapter notes explain momentum and how force is related to the change in motion of objects.
Support Better Problem Solving: Important concepts, formulas, and examples from the chapter are organised to help students apply force and motion principles effectively.