Apiston-cylinder device contains 0.02 m3 of hydrogen at 300 k. it has a diameter of 10 cm. the piston (assumed weightless) is pulled by a connecting rod perpendicular to the piston surface. if the outside conditions are 100 kpa and 300 k, (a) determine the pull force necessary in kn to create a pressure of 50 kpa inside. (b) the piston is now released; as it oscillates back and forth and finally comes to equilibrium, the temperature inside is measured as 600 k (reasons unknown). what is the pressure of hydrogen at equilibrium

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.