During a steady flow process, the pressure of a working substance drops from 200 to 20 psia, the speed increases from 200 to 100 ft/s, the internal energy of a working system decreases to 25 BTU/lb, and the specific volume increases from 1 to 8 ft3/lb. No heat is transferred. Sketch an energy diagram. Determine the work per lb. Is it done on or by the substance? Determine the work in hp for 10 lb/min.