A flywheel weighing 600 N has a radius of gyration of 300 mm.It starts rotation at 600 rpm and due to the viscosity of the fluid in the sleeve it is retarding at the rate of 1 rpm/s. The length of the sleeve is 50 mm and dia of the shaft is 20 mm and the radial clearance is 0.05 mm, calculate the viscosity of the fluid?