Question

Give reasons for the following A teacher moving around in the class is doing work but a child standing and reading a book is not doing any work.

Answer 1

A child reading a book while standing is not moving from its place i.e. displacement is zero. Hence the product of force and displacement is zero
W=F × S
W = mg × O = O
Hence, the child is not doing any work. Where as teacher is moving from its place is doing work