A rigid rod of mass 3.50 kg and length of 1.50 m rotates in a vertical (x,y) plane about a frictionless pivot through its center. Particles m1 (mass=6.30 kg) and m2 (mass=3.00 kg) are attached at the ends of the rod. Determine the size of the angular acceleration of the system when the rod makes an angle of 37.3o with the horizontal.