Three disks A, B and C with same radius 5.0 cm are placed at coordinate (0,50 cm), (-15 cm, 0), and (15 cm, 0), respectively as shown as Figure 1. The masses of the three disks are ma = 0.2 kg, mg = mc = 0.4 kg. They are connected by thin rods which has negligible masses. %3D A(0, 50) ma = 0.2 kg B(-15,0) C(15, 0) mB = 0.4 kg mc = 0.4 kg Figure 1 Find (a) the coordinate of the centre of mass of the system. (b) the rotational inertia about the axis perpendicular to the plane and passing through the centre of disk A.