A 54 kg person climbs a set of stairs at a constant speed from the second floor to the fourth floor in 24 s. The change in height from one floor to the next is 3.4 m. (a) Calculate the gravitational potential energy at the top of the climb. (b) Calculate the power of the person for the climb. (c) If a lighter person climbed the stairs in the same time, would this person's power be higher or lower? Explain.