An earth fill is constructed across a drainage. Closed contours at the 1000, 1040 and 1080 foot levels define areas of 680,000; 1,200,000; and 1,325,000 square feet respectively. Determine the acre-feet of water that can be impounded between the 1000 and 1080 foot levels by average end area and prismoidal methods.

Air (c-1.006 kj/kg.k, r-0.287 kj/kg.k) enters a nozzle steadily at 280 kpa and 77°c with a velocity of 50 m/s and exits at 85 kpa and 320 m/s. the heat losses from the nozzle to the surrounding medium at 20°c are estimated to be 3.2 kj/kg. determine (a) the exit temperature and (b) the total entropy change for this process. solve this problem using constant specific heats.