Power Required to Move Elevator Cab in NY Marriott Marquis

[goluigi2196]

1. An elevator cab in the New York Marriott Marquis has a mass of 4.15 x 10₃ kg and can carry a maximum load of 1.80 x 10₃ kg. If the cab is moving upward at full load at 3.57 m/s, what power is required of the force moving the cab to maintain that in kilowatts?W=Work P=Power t=Time F=Force d=distance g=gravity K=Kinetic Energy

Homework Equations

P=W/Δt
W=ΔK

therefore...
P=(1/2mv²)/Δt

The Attempt at a Solution

P=(1/2(4150+1800)²)/3.57

it's 4150+1800 because full load is 1800 kg and the elevator is 4150 kg.

solve for P and you get 5057500 W or 5057.5 kW

it says I'm wrong. What did I do wrong?EDIT

wow. fail. i forgot that it is divided by time, not velocity -_-

 

[gneill]

Hint: Another formula for power uses force and velocity.

 

[SteamKing]

It also didn't help that you squared the mass of the elevator cab and the payload in your original calculation.