sprinkler efficiency (urgent Ok, I have an exam on monday and both my lecturers and tutor have gone walkabouts. So you guys are my last resort. Thanks. :) Anyway: Water is discharged from a a garden sprinkler from two nozzles and opposite ends of an arm. Its the type that spins around and sprays water on your garden. I have calculated the torque exerted when its stationary but the second part of the question confuses me. It asks for the work done per second when spinning at speed "u". No worries. But then it asks for the efficiency of the device at that speed. Then asks for the value of "u" for maximum power. I dont understand how to find the efficiency of this, can someone explain how I would go about it?