CBSE Class 8 Answered

Friction is a necessary evil. There are instances in daily life where friction is a necessity.

Friction as a friend:

Friction plays a vital role in our daily life.

1. Construction of buildings is possible only because of friction.
2. We are able to write because of friction between the paper and the tip of the pen.
3. Without friction between our shoes and the ground, we will not be able to walk.
4. A horse cannot pull a cart unless friction furnishes him a secure Foothold.

Friction as a foe:

1. The main disadvantage of friction is that it produces heat in the moving parts of machines which causes wear and tear of the parts.
2. It opposes the motion.
3. A lot of energy is wasted in overcoming friction.
4. It causes wear and tear of the soles of shoes.
5. Due to friction, noise is also produced in machines.