A uniform 2.0 kg cylinder can rotate about an axis through its center at O. The forces applied are: F1 = 5.70 N, F2 = 3.90 N, F3 = 4.30 N, and F4 = 7.00 N. Also, R1 = 12.8 cm and R3 = 4.50 cm. Find the angular acceleration of the cylinder.