Question

An express lift (elevator) takes a 70 kg passenger from street level to the top of a 400 m skyscraper in 4 minutes. The mass of the elevator itself is 500 kg

a. How much gravitational potential energy does the passenger gain on the way up?

b. At what rate (energy per second) is the passenger gaining potential energy?

c. At what rate is the lift plus the passenger gaining potential energy?

d. What power is the lift plus the passenger experiencing as it climbs?

e. The motor driving the lift has an efficiency of only 25%. At what rate is the motor working as the lift is going up?

Answer 1