A 20ft x 20ft metal building has a steel roof that reaches atemperature of 140o F on a hot day. A cool front thenmoves in such that air at 60oF sweeps horizontallyacross the roof at a velocity of 10 ft/s. Assuming the rooftemperature remains at a constant 140oF for a time,determine:
a) the point at which the flow becomes turbulent (in feet)
b) the average heat transfer coefficient for the roof (inBTU/hr*ft^2*F)