A shock-free coupling for a low-power mechanical drive is to be made from a pair of concentric cylinders. The annular space between the cylinders is to be filled with oil. The drive must transmit power, P = 10 W. Other dimensions and properties are as shown in the schematic below. Neglect any bearing friction and end effects. Assume the minimum practical gap clearance d for the device is 8 = 0.25 mm. The company manufactures silicone fluids with viscosities as high as 10 centipoise. Determine the viscosity that should be specified to satisfy the requirement for this device. P = 10 W L = 20 mm R = 10 mm w2 2 9,000 rpm w1 = 10,000 rpm (outer cylinder) 8 = Gap clearance.