Colliding balls Two balls, of mass $m$ and mass $2 m$, approach from perpendicular directions with identical speeds $v$ and collide. After the collision, the more massive ball moves with the same speed $v$ but downward, perpendicular to its original direction. The less massive ball moves with speed $U$ at an angle $\theta$ with respect to the horizontal. Assume that no external forces act during the collision.
(a) Calculate the final speed $U$ of the less massive ball and the angle $\bar{\theta}$
(b) Determine how much kinetic energy is lost or gained by the two balls during the collision. Is this collision elastic, inelastic, or superelastic?