An elevator is constructed using an electric motor at the top which is used to lift the elevator's car via a cable. The cable weighs 6 pounds per foot. The cable is 100 feet long when the elevator car is at the first floor, and it is effectively 0 feet long when the car is at the top floor. The elevator's car weighs 500 pounds How much work W does the motor do just lifting the cable and car when it takes the car from the first floor to the top floor? W =