Suppose the viscous stress tensor at point p in a fluid is given by sigma = (sigma_xx 4 2 4 0 3 2 3 0) where sigma_xx is unknown. determine sigma_xx so that there is a plane with unit normal n on which the traction vector t = n middot sigma vanishes. determine n.

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]