An old, rough-surfaced, 2-m-diameter concrete pipe with a manning coefficient of 0.025 carries water at a rate of 5.0 m3/s when it is half full. it is to be replaced by a new pipe with a manning coefficient of 0.012 that is also to flow half full at the same flowrate. determine the diameter of the new pipe.

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]