Two objects are connected trough a pulley as shown in the figure below. You know that: m1 = 3.5 kg, m2 = 2.8 kg.' the mass of the pulley is 1.5 kg, its radius is 0.25 m and it rotates about a frictionless axis. (a) What is the minimal coefficient of kinetic friction between m2 and the surface that will prevent the pulley to rotate. Please include free body diagrams for all the three bodies and a well defined coordinate system. (b) The mass m2 started moving. The coefficient of kinetic friction is uk = 0.13. What is the angular acceleration of the pulley