Question

Name the three kinds of friction.

Answer 1

Hint: Friction is a resistive force, which comes into play when there is a relative motion between two bodies in contact. It is defined as the force due to the relative motion of solid surfaces, fluid layers, and material elements sliding, rolling, or rubbing against each other. Based on the movement of objects over each other, friction is classified into different types.

Complete answer:
In simple words, friction can be defined as the force that opposes the motion of a solid object over another object. There are three kinds of friction which are as follows:
1. Static friction: It is defined as the frictional force between the surfaces when they are at rest with respect to each other. Creating heat by rubbing both the hands together is an example of static friction.

2. Sliding friction/ Kinetic friction: It is the resistive force between two objects when they are sliding against each other. Two cards sliding against each other in a deck is an example of sliding friction.

3. Rolling friction: It is the resistive force between the moving surfaces when one rolls over another. Rolling of the log on the ground and wheels of moving vehicles are examples of rolling friction.

So, the three kinds of friction are Static friction, Sliding friction/ Kinetic friction, and Rolling friction.

Note: Students must remember that there are many other frictions including dry friction, pivot friction, and fluid friction. Static friction is usually greater than kinetic friction. Friction between two solids is independent of materials but depends upon the size of the contact zone, surface roughness, and load or pressure on the surface. It varies from material to material. Friction is also known as frictional force. Rolling friction is the weakest type of friction.