You push very hard on a heavy desk, trying to move it. You do work on the desk: You push very hard on a heavy desk, trying to move it. You do work on the desk: whether or not it moves, as long as you are exerting a force. only if it starts moving. never-it does work on you. only if it doesn't move. None of the above.

Only if it starts moving

Explanation:

Work done is defines as

In two case work done will be zero

First case is that when force and displacement are perpendicular to each other

What's more, other case is that when there is no displacement

So for work to be done there must have displacement,  in the event that there is no displacement then there is no work done

asthenosphere and convection