1.For use in a specialized underwater hoisting application, it is being proposed to design a disk clutch with a 20-inch outside diameter. Hard-drawn phosphor bronze is to be used in contact with chrome-plated hard steel to form the friction interfaces ( 0.03, 150 psi). The clutch must transmit 150 horsepower continuously at a rotational speed of 1200 revolutions per minute. Following a rule of thumb that says that for good design practice the inner diameter of a disk clutch should be about of the outer diameter, determine the proper num-ber of friction interfaces to use for this proposed clutch. Since the device operates under water, neglect temperature limitations.