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

80000 lb-ft

Explanation:

= Weight

h = Height

The work done by the car is

Weight of the cable is 6 pounds per feet

Total weight of cable

Work done to lift the cable

h = 50 as the CG will be center of the length of the cable

Total work done by the motor will be the sum of the work done

The work done to lift the car and motor is 80000 lb-ft

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min