Originally Posted by milski
Not sure what you're getting at about the masses. A real spring with a mass won't change much on its own - eventually, it will compress and the momentum of the spring and the object will become zero.
I don't want to confuse you if you already understand what's going on but I don't exactly get your point about masses.
i was thinking p=mv. if m = 0, then there is no momentum in an ideal spring as it compresses.