Question

In , friction is a friend.

• A. wearing of machines
• B. using pen for writing
• C. noisy machines

Answer 1

The correct option is B using pen for writing

Friction is called a necessary evil as it has many positive effects. For example, it is because of friction that we are able to walk and write. While writing, the ball inside the pen rolls because of the frictional force acting between the ball and the surface of the paper. Wearing of machines, noise and heat generation are not positive effects of the friction.