b) In a chemical process plant, hot air is to be cooled from 300C to 150C as it transported through a 10m long uninsulated square duct of cross section 0.15m0.15m. The hot air enters the duct at atmospheric pressure with a mean velocity of 5m/s. The walls of the duct are maintained at 100C. Given the properties of hot air are: =0.7662kg/m3 and Cp=1023J/kgC. Determine the rate of heat transfer (Q) and heat transfer coefficient (h) between the hot gases and the duct. (10 marks)