4. Two masses are connected by a string passing over a frictionless pulley as in the figure. The pulley is a 5kg, 0.5 m radius ring connected to the rim of a 4 kg solid disk. The ramp has a kinetic friction coefficient /x = 0.4. (a) Determine the magnitude of the system's acceleration. 1.659 m/s 10 kg 15 5 kg (b) What is the net torque on the pulley? 5.807 N . m