posted by Jack Hill .
container factory uses a 450 W motor to operate a conveyor belt that lifts containers from one
floor to another. To lift 250 1-kg containers a vertical distance of 2.4 m, the motor runs for 45 s.
What is the efficiency of the motorized conveyor system?
Work output = 250*g*2.4 = 5880 joules
Work input = 450*45 = 20,250 joules
For the efficiency, take the output/input ratio