Four small disks A, B, C, and D can slide freely on a frictionless horizontal surface. Disks B, C, and D are connected by light rods and are at rest in the position shown when disk B is struck squarely by disk A which is moving to the right with a velocity v0 = (12 m/s)i. The masses of the disks are mA = mB = mC = 7.5 kg, and mD = 15 kg. Knowing that the velocities of the disks immediately after the impact are vA = 0, vB = (3.5 m/s)i, vC = vCi, and vD = vDi, determine

(a) The speeds vC and vD,

(b) The fraction of the initial kinetic energy of the system which is dissipated during thecollision.

C B D 0.9 m 0.9 m