Say whether work is done on the object in the physics meaning, and give a reason, in each case.

Say whether work is done on the object in the physics meaning, and give a reason, in each case.

1. A boy pushes a loaded wheelbarrow, and it moves along the path.
2. A girl pushes hard against a parked truck. The truck does not move.
3. A coolie stands still with a heavy box on his head.
4. A man walks along a level road carrying a bucket.
5. A crane lifts a steel beam to the top of a building.