You have tried to lift an object unsuccessfully, without realizing that the object was attached to the floor. During this process you have become exhausted. Which one of these explains your activity according to physics?

1. You did no work on the object because you didn't a apply a force.
2. You did work on the object, that is why you are tired.
3. You did no work on the object because it did not move.
4. You did work on the object, but the work is now gone because you have stopped.