Consider the incompressible viscous flow of air between two infinitely long parallel plates separated by a distance h. Both plates are stationary, but a constant pressure gradient exists in the flow direction (i. e. dp / dx= constant ).a. Obtain an expression for the variation of velocity between the plates. b. Obtain an expression for the shear stress on the plates in term of dp / dx.

Burgers vector is generally parallel to the dislocation line. a)-true b)-false

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]

The proportional limit is always greater than the yield strength for a material. a)-trune b)- false