Introduction

CBSE notes class 8 friction has a significant importance in building a proper concept of science for class 8. There is a detailed explanation of the frictional force, its characteristics, and it also helps to understand the necessity of friction. This blog article involves the friction class 8 notes to help the students grasp the concept of friction in a simple way.  

What is friction?

Friction is a force that acts when two surfaces come into contact. The force of friction acts in the opposite direction to the motion of an object. It opposes the relative motion of the surfaces of two moving objects.

Effects of friction 

There is are significant impact of friction on an object:

• Friction can produce heat. 
• Friction opposes motion and decreases the speed.
• Friction leads to wear and tear. 
• A heavy object may experience more friction than a light object, as the contact force will increase between the two surfaces. 

Factors that affect friction 

Several factors influence the friction:

1. Uneven surface: If we move an object with an irregular surface on an uneven surface, then the friction will be high and the movement of that object will be restricted.
2. Smooth surface: If the surface of the object or the surface on which it is moving is smooth, then the frictional force will be less, and the object can move easily.
3. Contact between two surfaces: If the two surfaces are pressed against each other, the force of friction will hardly increase. In this case, the movement of the object will be restricted. 

Types of friction 

The types of friction have been included in the friction class 8 notes to explain the characteristics of the frictional force. 

1. Static friction – Static friction acts on a motionless object. To start the movement, an object has to overcome the static friction force. The force is always equal as well as opposite to the applied force on the object. The force that comes to play when a body is at the point of sliding on a surface is called limiting friction. 

2. Rolling friction 

The friction that acts between two surfaces when one object rolls over another object is called Rolling friction. Rolling friction is less than sliding friction. 

3. Sliding friction 

Sliding friction comes into play when an object moves on the surface of another object. This movement is known as a slide. Sliding friction acts in the opposite direction to which the object slides. Sliding friction is less than static friction. 

4. Fluid friction 

When an object moves in a liquid, the liquid exerts a force upon the object. This force is called fluid friction.

How to increase friction?

• By applying heavy pressure between two surfaces, we can increase the frictional force. 

Example- In a cycle, the brake pads press against the moving part of the wheel, which increases the frictional force. 

• The force of friction can also be increased by enhancing the roughness of the surfaces that come into contact with each other. 

Example- The threading of shoes or tyres is done to increase the friction to avoid the risk of slipping on the roads.

How to decrease friction?

• The friction between two objects can be reduced by making the surfaces smooth on which they are coming into contact. 
• Sliding friction between the moving parts of a machine can be reduced by applying grease, oil, graphite, or other lubricants.  
• Friction can be reduced by using wheels in bags. 
• Fish, boats, airplanes, and birds have streamlined shapes of body that help to mitigate the fluid friction. 

Advantages of friction

Frictional force is essential for various daily activities. The benefits of friction are as follows:

• A moving object can not come into a state of rest in the absence of a frictional force.
• We can not be able to walk on a surface without a frictional force.
• Frictional force allows us to write with a pen on the surface of a paper.
• It will be impossible to drive a car on the road without a frictional force.
• Fixing a nail in the wall is possible because of the frictional force.

Disadvantages of friction

Though there are several advantages of the frictional force, it involves some drawbacks. The disadvantages are discussed here,

• Frictional force leads to wear and tear of objects, such as the moving part of a machine that becomes damaged, or the sole of a shoe that is torn after long use. 
• Frictional force causes a decrease in the speed of a moving object.
• The machine can be heated up due to the frictional force. The production of heat causes the wastage of energy.

Fluid friction

• Fluid can flow due to the force or pressure applied to it, and the force of friction of the liquid opposes the motion of an object moving through it is called the fluid friction.  
• The force of fluid friction depends on the speed, shape, and nature of the object. 
• The object can lose speed and energy due to the friction and effort needed to cop with the friction. 
• The special type of shape of the bodies of fish and birds can minimise the friction.

Conclusion 

Friction Class 8 Notes highlights the concept of different types of friction, the effects of friction, and the factors that affect frictional force. The advantages as well as the disadvantages of friction have also been discussed here. It explains in simple terms how the frictional force works in our daily activities.  Friction class 8 notes are essential for the board exam preparation as they emphasize the key topics of friction. It simplifies the complex concept by explaining it through real-life examples.

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