Question

Friction is an necessary evil? explain with an example

Answer 1

friction is said to be a necessary evil because it is useful as well as harmful. friction helps us to walk, write, hold things, lift objects. So it is necessary in our lives. Without friction many essential processes can not be done. On the other hand, it is also unecessary at times. it sometimes results in loss of energy, wear and tear of parts of machinery, due to which it also damages things. so it is an essential evil. Hope this helps!

Answer 2

Friction is necessary:
If there is anything which moves forward with respect to something else while in contact with it without any external force acting 
Friction is evil:
If there is external force available then the same friction slows it down.