A0.320 kg puck at rest on a horizontal frictionless surface is struck by a 0.220 kg puck moving in the positive x direction with a speed of 4.09 m/s. after the collision, the 0.220 kg puck has a speed of 1.29 m/s at an angle of θ = 60.0° counterclockwise from the positive x axis. (a) determine the velocity of the 0.320 kg puck after the collision. express your answer in vector form. vf = m/s (b) find the percent of kinetic energy lost in the collision.