Question

Then where is zero work done examples what is meant by zero work done

Answer 1

Zero work done means where no work is done.
For ex :-pushing a wall

Answer 2

Work =F S costhita.
work is said to be done when there is an applied force and displacement with an angle(thita is not equal to 90).
when cos thita is 90,then the work done is Zero As,cos 90 is 0.
(or)
If the applied force is 0.
(or)
displacement is 0.
Example,A coolie carrying luggage.