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]

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.

Avolume of 2.65 m3 of air in a rigid, insulated container fitted with a paddle wheel is initially at 264 k, 5.6 bar. the air receives 432 kj by work from the paddle wheel. assuming the ideal gas model with cv = 0.71 kj/kg • k, determine for the air the amount of entropy produced, in kj/k