1. Air whose density is 0.078 lbm/ft3 enters the duct of an air-conditioning system at a volume flow rate of 450 ft3 /min. If the diameter of the duct is 10 in, determine the velocity of the air at the duct inlet and the mass flow rate of air.
2. Air enters a 28-cm diameter pipe steadily at 200 kPa and 20°C with a velocity of 5 m/s. Air is heated as it flows, and leaves the pipe at 180 kPa and 40°C. Determine
(a) the volume flow rate of air at the inlet,
(b) the mass flow rate of air, and
(c) the velocity and volume flow rate at the exit.
