Air enters the duct of an air-conditioning system at 15 psia and 50F at a volume flow

Question:

Air enters the duct of an air-conditioning system at 15 psia and 50°F at a volume flow rate of 450 ft3/min. The diameter of the duct is 10 in, and heat is transferred to the air in the duct from the surroundings at a rate of 2 Btu/s. Determine
(a) The velocity of the air at the duct inlet and
(b) The temperature of the air at the exit.