Answer to Question #97787 in Physics for Nyx

Question

An elevator of mass m is initially at rest on
the first floor of a building. It moves upward,
and passes the second and third floors with
a constant velocity, and finally stops at the
fourth floor. The distance between adjacent
floors is h.
What is the net work done on the elevator
during the entire trip, from the first floor to
the fourth floor?
1. W = −4 m g h
2. W = 0
3. None of these.
4. W = 3 m g h
5. W = 4 m g h
6. W = −3 m g h

Answer 1

$$W=n\Delta E_p$$

$$\Delta E_p=mgh$$

$$W=3mgh$$

Answer: 4. W = 3 m g h