The read-write head for a hand-held music player has a surface area of 0.04 mm. The head is held 0.04 m above the disk, which is rotating at a constant rate of 1800 rpm. Determine the torque T that must be applied to the disk to overcome the frictional shear resistance of the air between the head and the disk. The surrounding air is at standard atmospheric pressure and a temperature of 20C. Assume the velocity profile is linear. 8 mm