What are the general effects of friction?

Friction produces heat. Friction causes wear and tear. Friction opposes motion.

Define Fluid Friction and the factors that affect the fluid friction?

Fluids are the substance which can flow on application of force or pressure on them.Gases and Liquids are fluids. The force of friction exerted by the fluids on the objects moving through them is called fluid friction. The frictional force produced by fluids is known as drag. Factors that affect the Fluid Friction Speed of the object in the fluid Shape of the object moving in the fluid Nature of the Fluid.

How Friction can be reduced?

Friction is reduced by providing wheels, e.g. suitcase, school bags of kids, etc. Substances that decrease friction are known as lubricants. Friction in the midst of the sliding surfaces of two objects can be decreased by smoothing the contact surfaces through polishing.

What causes force of friction?

Friction occurs between two surfaces because of the irregularities on their contact surfaces, the interlocking of microscopic features, and the way harder surfaces can embed themselves into smoother ones.

What are the types of friction?

Static Friction:When an object is stationary , the frictional force is known as static friction and is always equal and opposite to the implemented force. The frictional force that occurs when the object is on the brink of sliding is referred to as limiting friction. Sliding friction: The frictional force that resists the actual sliding motion between two contacting surfaces is known as sliding friction, which is generally less than static friction. Rolling Friction:The frictional force that occurs between two surfaces when one body rolls over the other is called rolling friction, and it is typically less than sliding friction.

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CBSE Notes

Class 8

Science

Chapter 9 Friction

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CBSE Class 8 Syllabus

Class 8 syllabus allows students to create a structured study plan, allocating time to each subject and topic based on its weightage and importance.

CBSE Class 8 Notes

CBSE Class 8 Notes are important for students who want to prepare effectively for the exam. They are....

CBSE Class 8: A Comprehensive Overview

The Central Board of Education (CBSE) administers the class 8 exam, a prerequisite for all NCERT-based schools to be affiliated with CBSE. The students...

NCERT Solutions Class 8

NCERT Solutions is an important study material, and it provokes the student to revise any topic very efficiently...

CBSE Exam 2026

CBSE is a national-level board of education in India, responsible for public and private school education, and is managed by...

Important CBSE Science Topics

Science is, therefore, a systematic enterprise that organizes and builds testable explanations and predictions...

CBSE Notes

Class 8

Science

Chapter 9 Friction

CBSE Notes Class 8 Science Chapter 9 Friction

Friction is a key force that resists the relative motion between two surfaces in contact. It significantly impacts our daily activities, impacting everything from walking and driving to the operation of machinery. To fully grasp the concept of friction, it’s important to explore its various types—static, kinetic (or sliding), rolling, and fluid friction—each of which has unique properties and uses.

1.0Download CBSE Class 8 Science Chapter 9 Friction Notes : Free PDF

Download FREE PDF notes for CBSE Class 8 Science Chapter 9 – Friction. Learn about static, sliding, and rolling friction, and how friction affects motion in our daily lives.

Class 8 Science Chapter 9 Revision Notes:

2.0Friction

It is a force that resists the relative motion between two surfaces in contact. It consistently acts in the direction opposite to the applied force.
It is always parallel to the surfaces in contact

3.0Causes of Friction

Friction arises between two surfaces because of surface irregularities, the interlocking of microscopic features, and the way harder surfaces can dig into smoother ones.

4.0Factors Affecting Friction

Surface roughness
The degree of contact between the two surfaces
Characteristics of the surfaces

Friction-A Necessary Evil: Friction can be seen as a friend because it offers advantages, but it also has its drawbacks, making it a foe at times. Depending on the situation, friction can either resist or obstruct us, which is why it's often viewed as a necessary evil.

Friction is useful in many cases:

Friction is required to hold vessels like glass tumblers.
Friction is useful for brakes and tyres.
You Could not tie a knot without friction.

5.0Increasing and Reducing Friction

Increasing Friction: By applying greater pressure between the surfaces, such as when brakes are engaged on a cycle or car, the brake pads press against a moving part of the wheel, resulting in an increase in frictional force.
Friction can be enhanced by increasing the roughness of the contacting surfaces. For instance, the treads on shoes and tires are designed to boost friction.
Reducing Friction: Friction between the gliding surfaces of two objects can be minimized by smoothing the contact surfaces through polishing.
Substances that decrease friction are known as lubricants.
Sliding friction between the moving components of vehicles and machinery can be decreased by applying lubricants such as oil, grease, graphite, or other similar substances.
Rolling friction is lower than sliding friction. Therefore, sliding friction is often substituted with rolling friction by using rollers, such as ball bearings, between the hub and axles in the moving parts of machines and vehicles.
Friction is minimized by incorporating wheels, as seen in items like suitcases and children's school bags.
Aeroplanes, boats, fish, and birds have specially shaped bodies known as streamlined shapes to minimize fluid friction and prevent energy loss during movement.

6.0Types of Friction

Static Friction: When an object is stationary, the frictional force is known as static friction and is always equal and opposite to the implemented force. The frictional force that occurs when the object is on the brink of sliding is referred to as limiting friction.
Sliding friction: The frictional force that resists the actual sliding motion between two contacting surfaces is known as sliding friction, which is generally less than static friction.
Rolling Friction: The frictional force that occurs between two surfaces when one body rolls over the other is called rolling friction, and it is typically less than sliding friction.

7.0Effects of Friction

Friction produces heat.
Friction causes wear and tear.
Friction opposes motion.

8.0Advantage and Disadvantage of Friction

Advantages of Friction

Friction between a pen and paper enables us to write. Friction between our feet and the ground facilitates movements such as standing, walking, and running. Additionally, friction between the road surface and vehicle tires allows for movement without slipping.

Disadvantages of Friction

Friction slows down or stops moving objects. It generates heat, leading to energy loss in machines. Additionally, friction contributes to the wear and tear of moving parts in machinery and the soles of shoes.

9.0Fluid Friction

Fluids are the substance which can flow on application of force or pressure on them. Gases and Liquids are fluids.
The force of friction exerted by the fluids on the objects moving through them is called fluid friction.
The frictional force produced by fluids is known as drag.

Factors that affect the Fluid Friction:

Speed of the object in the fluid
Shape of the object moving in the fluid
Nature of the Fluid.

10.0Key Features of CBSE Notes Class 8 Science Chapter 9 Friction

Explains what friction is and how it acts as a force.
Covers different types of friction – static, sliding, rolling, and fluid.
Describes factors affecting the amount of friction between surfaces
Understand the advantages and disadvantages of friction.

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Class

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Preferred Programs

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CBSE Class 8 Syllabus

Class 8 syllabus allows students to create a structured study plan, allocating time to each subject and topic based on its weightage and importance.

CBSE Class 8 Notes

CBSE Class 8 Notes are important for students who want to prepare effectively for the exam. They are....

CBSE Class 8: A Comprehensive Overview

The Central Board of Education (CBSE) administers the class 8 exam, a prerequisite for all NCERT-based schools to be affiliated with CBSE. The students...

NCERT Solutions Class 8

NCERT Solutions is an important study material, and it provokes the student to revise any topic very efficiently...

CBSE Exam 2026

CBSE is a national-level board of education in India, responsible for public and private school education, and is managed by...

Important CBSE Science Topics

Science is, therefore, a systematic enterprise that organizes and builds testable explanations and predictions...

CBSE Notes Class 8 Science Chapter 9 Friction

Friction is a key force that resists the relative motion between two surfaces in contact. It significantly impacts our daily activities, impacting everything from walking and driving to the operation of machinery. To fully grasp the concept of friction, it’s important to explore its various types—static, kinetic (or sliding), rolling, and fluid friction—each of which has unique properties and uses.

1.0Download CBSE Class 8 Science Chapter 9 Friction Notes : Free PDF

Download FREE PDF notes for CBSE Class 8 Science Chapter 9 – Friction. Learn about static, sliding, and rolling friction, and how friction affects motion in our daily lives.

Class 8 Science Chapter 9 Revision Notes:

2.0Friction

It is a force that resists the relative motion between two surfaces in contact. It consistently acts in the direction opposite to the applied force.
It is always parallel to the surfaces in contact

3.0Causes of Friction

Friction arises between two surfaces because of surface irregularities, the interlocking of microscopic features, and the way harder surfaces can dig into smoother ones.

4.0Factors Affecting Friction

Surface roughness
The degree of contact between the two surfaces
Characteristics of the surfaces

Friction-A Necessary Evil: Friction can be seen as a friend because it offers advantages, but it also has its drawbacks, making it a foe at times. Depending on the situation, friction can either resist or obstruct us, which is why it's often viewed as a necessary evil.

Friction is useful in many cases:

Friction is required to hold vessels like glass tumblers.
Friction is useful for brakes and tyres.
You Could not tie a knot without friction.

5.0Increasing and Reducing Friction

Increasing Friction: By applying greater pressure between the surfaces, such as when brakes are engaged on a cycle or car, the brake pads press against a moving part of the wheel, resulting in an increase in frictional force.
Friction can be enhanced by increasing the roughness of the contacting surfaces. For instance, the treads on shoes and tires are designed to boost friction.
Reducing Friction: Friction between the gliding surfaces of two objects can be minimized by smoothing the contact surfaces through polishing.
Substances that decrease friction are known as lubricants.
Sliding friction between the moving components of vehicles and machinery can be decreased by applying lubricants such as oil, grease, graphite, or other similar substances.
Rolling friction is lower than sliding friction. Therefore, sliding friction is often substituted with rolling friction by using rollers, such as ball bearings, between the hub and axles in the moving parts of machines and vehicles.
Friction is minimized by incorporating wheels, as seen in items like suitcases and children's school bags.
Aeroplanes, boats, fish, and birds have specially shaped bodies known as streamlined shapes to minimize fluid friction and prevent energy loss during movement.

6.0Types of Friction

Static Friction: When an object is stationary, the frictional force is known as static friction and is always equal and opposite to the implemented force. The frictional force that occurs when the object is on the brink of sliding is referred to as limiting friction.
Sliding friction: The frictional force that resists the actual sliding motion between two contacting surfaces is known as sliding friction, which is generally less than static friction.
Rolling Friction: The frictional force that occurs between two surfaces when one body rolls over the other is called rolling friction, and it is typically less than sliding friction.

7.0Effects of Friction

Friction produces heat.
Friction causes wear and tear.
Friction opposes motion.

8.0Advantage and Disadvantage of Friction

Advantages of Friction

Friction between a pen and paper enables us to write. Friction between our feet and the ground facilitates movements such as standing, walking, and running. Additionally, friction between the road surface and vehicle tires allows for movement without slipping.

Disadvantages of Friction

Friction slows down or stops moving objects. It generates heat, leading to energy loss in machines. Additionally, friction contributes to the wear and tear of moving parts in machinery and the soles of shoes.

9.0Fluid Friction

Fluids are the substance which can flow on application of force or pressure on them. Gases and Liquids are fluids.
The force of friction exerted by the fluids on the objects moving through them is called fluid friction.
The frictional force produced by fluids is known as drag.

Factors that affect the Fluid Friction: