In a 45-degree bend pipe on horizontal plane a circular air duct of 3.5 m^2 cross sectional area is gradually reduced to 1.2 m^2 area. Find the pressure in N/cm^2 at 1.5 m^2 cross sectional area, if the velocity of flow at the 2.1 m^2 section is 10.0 m/s and pressure is 3.453 N/cm^2. Take density of air is 1.18 kg/m^3.

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]