The disk A rolls without slipping on a horizontal surface. End B of bar BC is pinned to the edge of the disk A, and end C of the bar BC can slide freely along the horizontal surface. In addition, bar BC is pushed by the force P D mg at its left end. The mass of bar BC is mBC , and the mass of the disk A is mA. The system is initially at rest. Determine the acceleration of the center of the disk A and the angular acceleration of bar BC immediately after the force P is applied if mA D mBC D m.