Acylindrical part of diameter d is loaded by an axial force p. this causes a stress of p/a, where a = πd2/4.

if the load is known with an uncertainty of ±12 percent, the diameter is known within ±3 percent (tolerances), and the stress that causes failure (strength) is known within ±17 percent, determine the minimum design factor that will guarantee that the part will not fail.

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.