Question

state the condition under which work is said to be have done

Answer 1

when displacement is not zero

Answer 2

HI

HERE IZ UR ANSWER.

Work = Force * Displacement

which means for a work done to be said you have to apply the force and there should be some displacement.

Zero work done is the case when there is force applied and no displacement.
for example - If u push a concrete wall, there will be no displacement but there will be force applied.

There are 2 types of work done :-

Positive work done
Negative work done

Positive is when the direction of force applied and displacement of body is same.
for example - If u kick a stationery ball, then it will move in the dirn where u have kicked, this is positive work done.

Negative is when the direction of force applied and displacement is not same.

for example - If u kick a fast moving ball, and u kicked it, then direction of displacement will not be the same as the direction of force applied.

HOPE IT HELPS