Please forgive me for my naiveté but I've got to resolve a conceptual problem I'm having. If every action has an equal and opposite reaction then why don't all the forces in the universe cancel each other out. For example if i am in space and I hit a ball with force X then the ball reacts back with force X which would mean the forces cancel each other meaning there would be no resultant force and therefore no movement. I know this is nonsense but I'm just giving you an idea of the conceptual difficulty I'm having. If anyone could resolve this I would be very appreciative. Thanks!