If i have 2 circular objects like coins and their moving on a frictionless surface and i know their velocity angles mass, how can i find the angle of each object after they collide, an example A is the first coin, B the second their masses are the same. X will be the x of a vector and Y the y part. if A's velocity vector was (4X, 0Y) and B's is (-2X, 0Y) i know they would of course after a head on collision bounce back and continue to move across the X axis, and also swap speeds, so in this case i believe they would just swap velocity vectors. but of course theirs many different angles and such they could collide and rarely would it be head on. and im not sure how i would find the angle in any of those cases.