A cable is wound around the hub of a spool that has a mass of 50 kg and center of gravity at G, and is connected to a block with a mass of 30 kg. It is known that the coefficients of static friction are 0.15 under the spool and 0.2 under the block. Compute the maximum counterclockwise moment of a couple Co that can be applied without disturbing the equilibrium of the system
