How the Elevator Works


Noel is an electric engineer who is designing an elevator for the new
wing of the library. The elevator needs to carry new books to the fourth floor where
the university bookstore is located. The elevator is always
fully loaded when it travels upwards and empty when it travels downwards.
The main power line was installed when the library was built, hence the
power for this elevator is limited. Noel needs to make sure his design is feasible
for the power requirement.
What is known:
 The mass of the empty car m_{car} = 150 kg
 The maximum load is m_{load} = 650 kg
 The mass of the counterweight is 50% of the total mass of the elevator when it is fully loaded
 The operating velocity of the elevator is v = 2.0 m/s
