Read the following case and answer the following quesiton:
Ravi was helping his father move furniture in their house. He pushed a cupboard with a constant force of \(60\ N\), and the cupboard moved \(4\ m\) across the floor. Later, he tried to push a wall with the same force, but the wall did not move. After finishing the work, Ravi switched on an electric fan and noticed that it started rotating immediately.
What is the SI unit of work done?