Metal disks need to be cooled from 150 Celsius to 80 Celsius by blowing 70 Celsius air on top of them. Both disks are identical and have a mass of 100 grams, diameter of 20 cm, and thickness of 0.5 cm. Heat capacity of the disks are 2 J/g*C. Determine time required to reach 80 Celsius while assuming heat transfer coefficient of h=W/m^2*C. Assume both disk's entire surface area is hit by the air flow.