I am trying to analyze the physics of a 2d collision among polygons. I supplied you with an image that illustrates my attempt: http://s278.photobucket.com/albums/kk112/beloxx/?action=view¤t=collision.jpg" [Broken] http://s278.photobucket.com/albums/kk112/beloxx/?action=view¤t=collision.jpg Now, object A moves with a velocity Vi while object B is still, as indicated on the image. According to my analysis, object A will transfer its velocity (momentum) through point P to object B which will receive the velocity with a vector perpendicular to the normal (blue line). This will further decompose into angular and transitional velocities which i have no problem doing. When I tried to simulate that with a program (when a point hits a figure, the collision looks realistic) however what I am confused about is the final velocity of object A after hitting object B, or to be more precise the direction of the final velocity.... Does anyone have any idea? Any help will be greatly appreciated.