Suppose a person walks up the stairs of an escalator when it (the escalator) is moving upwards. What is the work done by the escalator on the person? Is it the same as if the person were standing still?
I think it is not the same because the person is pushing the stairs down, so the normal force must be greater than the weight of the person, which means the escalator does a greater work. I think that part of this greater work is converted into kinetic energy, since the person is moving with respect to the escalator. Is my reasoning correct?
Best Answer
The elevator has to perform more work in the moment the person is accelerating upwards, but then again less work when stopping at the top, i.e. decelerating. In total, the work performed by the elevator is therefore the same as if the person was standing still the whole time.