Acylindrical metal specimen having an original diameter of 11.86 mm and gauge length of 54.0 mm is pulled in tension until fracture occurs. the diameter at the point of fracture is 6.59 mm, and the fractured gauge length is 73.0 mm. calculate the ductility in terms of (a) percent reduction in area (percent ra), and (b) percent elongation (percent el).

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]