A `90-kg` man runs up an escalator while it is not in operation in `10s`. What is the average power developed by the man. Suppose the escalator is running so that the escalator steps move at a speed of `0.5m^-1`. What is then the power developed by the man as seen by the ground reference if he moves at the same speed relative to the escalator steps as he did when the escalator is not in operation?