A 58.0-kg man is riding an escalator in a shopping mall. The escalator moves the man at a constant velocity from ground level to the floor above, a vertical height of 3.70 m. What is the work done on the man by (a) the gravitational force and (b) the escalator?

Answer 1

change in potential energy = m g h
the gravitation force is opposite to the direction of motion so work done = -m g h
the escalator force is in the direction of motion so work done by it is +m g h

Answer 2

58.0*9.8*3.70
=-2100 j 3 sig fig

b) 2100 j 3 sig fig

thanks Damon