A thin, flat plate that is 0.2 m by 0.2 m on a side with extremely rough top and bottom surfaces is placed in a wind tunnel so that its surfaces are parallel to an atmospheric air stream having a velocity of 30 m/s. The air is at a temperature of Too = 20°C while the plate is maintained at Ts = 80°C. The plate is rotated 45° about its center point as shown in the schematic. Air flows over the top and bottom surfaces of the plate, and measurement of the heat transfer rate is 2000 W. What is the drag force on the plate?
