A Pelton wheel is supplied with water from a lake at an elevation H above the turbine. The penstock that supplies the water to the wheel is of length , diameter D, and friction factor f. Minor losses are negligible. Show that the power developed by the turbine is maximum when the velocity head at the nozzle exit is 2H/3. Note: The result of Problem 12.61 may be of use.

A)-in the process of engineering design, explain the contribution of material selection. b)- explain the procedure of synthesis as is employed in engineering design. c)- is there any relationship between ergonomics and engineering design? explain. d)- safety consideration in engineering design includes human, product and the enviroment . explain how safety will be incorporated into the design?