A gear reduction system consists of three gears A, B, and C. Gear A starts from rest at time t=0 and rotates clockwise with constant angular acceleration. Knowing that the angular velocity of gear A is 600 rpm at time t=2 s, determine a) the angular accelerations of gears B and C, b) the accelerations of the points on gears B and C which are in contact when t = 0.5 s.