Certain elements of an in-refrigerator ice-cube maker are shown in the figure. (A "cube" has the form of a cylindrical segment!) Once the cube freezes and a small heater (not shown) forms a thin film of water between the cube and supporting surface, a motor rotates the ejector arm OA to remove the cube. If there are eight cubes and eight arms, determine the required torque M as a function of (). The mass of eight cubes is 0.25 kg, and the center- of-mass distance r = 0.55r. Neglect friction, and assume that the resultant of the distributed normal force acting on the cube passes through point O.
