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. Initially ball A is moving upward along the y axis at 1.5 m/s, and ball B is moving to the right along the x axis with speed 4.0 m/s. After the collision (assumed elastic), the second ball is moving along the positive y axis (see figure). http://www.webassign.net/gianpse4/9-43alt.gif (a) What is the final direction of ball A? ______° (counterclockwise from the +x axis is positive) (b) What are their two speeds? v'A =____ m/s v'B =____ m/s 2. Relevant equations 3. The attempt at a solution a) 90+45=135° b) I am not sure where to begin....I know that KE is conserved, so momentum before is equal to momentum after.