I have a problem with this question, 1. Two rolling golf balls of the same mass collide. The velocity of one ball is initially 2 m/s [E] After the collision, the velocities of the balls are 2.49 m/s [62.8° North of West] and 2.37 m/s [69.2° South Of East]. What are the magnitude and direction of the unknown velocity? Basicall I did: For x component: V1 + V2 = V1'cos(180°-62.8°) + V2'cos(360°-69.2°) I solved for V2 I did the same for the y component then I took the x and y component values and did the pythagoras theorem to get the angle and value...The value at the back of the book is 3 m/s and moving W for the initial velocity of the other ball...My answer was 4.7 m/s [20° South of West] Whats my mistake?