Hello; I am a little confused here. A friend asked me that, due to Newton's Third Law of Motion, for every force there is an equal and opposite force. Therefore, why is it, for example, that when we throw a ball up into the air, it moves upwards at all, if the force exerted on the ball upwards is the same downwards (plus gravity)? Same thing for a rocket - if the rocket applies, say, a 10000N force upwards, and if there is a 10000N force downwards acting on the rocket, why does it still move? I just need to get this cleared up as I know I am missing something important here. Thanks.