A man is running down an inclined plane. Is he doing work or is work being done on him? Why is it that under normal circumstances when we are running down an inclined plane we feel that we are doing work?

Explanation

Work is being done by gravity on the man. The man loses height as he races down the inclined plane. Normally, we feel that we are doing work, as we have to prevent ourselves from moving too fast. In this process, we do work by reducing our kinetic energy resulting from the decrease in height.