A 55 kg engineer leaves her office on the 33rd floor of askyscraper and takes an elevator to the 59th floor. Later shedescends to street level. If the engineer takes her office as thezero for potential energy and if the distance from one floor to thenext is 3.5 m, what is the engineer's potential energy
(a) in her office,
(b) on the 59th floor, and
(c) at street level?