Excuse the Title =X 1. The problem statement, all variables and given/known data A 0.300 kg puck, initially at rest on a horizontal, frictionless surface, is struck by a 0.200 kg puck moving initially along the x axis with a speed of 2.00 m/s. After the collision, the 0.200 kg puck has a speed of 1.00 m/s at an angle of [tex]\Theta[/tex]= 50.0° to the positive x axis. http://img265.imageshack.us/img265/5695/811vx2.gif [Broken] Determine the speed of the 0.300 kg puck after the collision. 2. Relevant equations m1v1i + m2v2i = (m1 + m2)vf 3. The attempt at a solution total momentum before collision = 0 total momentum after collision = 0.3 * v1f *sin 50 - 0.2 * v2f *sin φ from the law of conservation of momentum , 0.3 * v1f * sin 50 - 0.2 * v2f * sin φ = 0 0.3 * v1f * sin 50 = 0.2 * v2f * sin φ where v2f = 1 m / s φ = 90 - 50 = 40 so: (0.3)(v1f)(sin50) - (0.2)(1)(sin40) = 0.5596 m/s ??