1. The problem statement, all variables and given/known data Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Ball A is moving upward along the y axis at 2.0 m/s and ball B is moving to the right along the x axis with speed 3.7 m/s. After the collision (elastic), ball B is moving along the positive y axis. What is the final direction of ball A and what are their two speeds? 2. Relevant equations mAvA + mBvB = mav'A + mBv'B 1/2mAvA2 + 1/2mBvB2 = 1/2mAv'A2 + 1/2mBv'B2 3. The attempt at a solution I know that because this is an elastic collision, momentum and kinetic energy are conserved. I think it's just that the two balls start on different axes is what's throwing me off.