An alpha particle collides with an oxygen nucleus, initially at rest. The alpha particle is scattered at an angle of 64.0 above its initial direction of motion and the oxygen nucleus recoils at an angle of 51.0 below this initial direction. The final speed of the oxygen nucleus is 1.20 105 m/s. What is the final speed of the alpha particle? (The mass of an alpha particle is 4.00 u and the mass of an oxygen nucleus is 16.0 u.)