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).

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.