Question

In which of the following cases friction is undesirable?

A) while we walk on the road.

B) Brake pads of cycle used to stop the wheel.

C) Ball-bearing in machines parts.

D) while we write on paper with ball pen.​

Answer 1

Everything mentioned here is desirable so none of the above mentioned

Answer 2

Answer:

c)

Explanation:

Ball-bearing in machines parts.

because here it reduce energy.

when we walk on road there should be friction otherwise we will be unable to walk.

to stop the bike friction is necessary other how we can stop bike.

due to friction between paper and ball the

ball inside the tip of pen roll on paper and distribute ink to the paper.