Q49 of 100 Page 231

A pencil eraser loses tiny pieces of rubber each time you use it. Why does this happen ?

This is because the paper surface offers more friction to the pencil rubber when we rub on the paper, some bits of rubber come on the paper.

Which parts wear away first in shoes? Give a reason for your answer.

Why do brake pads of bicycles have to be replaced quite often?

What happens when you rub your hands vigorously for a few seconds ? Why does this happen ?

Explain how, friction enables us to walk without slipping.