A.T. and TurtleMeister:
Thank you. Sorry I forgot to mention in the OP that I know about elastic collisions. I understand that, at least during the collision,
momentum is conserved along with energy. But then the strings pull the balls into a circular path.
In the picture there are five balls. If you pull one back and let it smash into the other four, it transfers all its momentum and energy, and the ball on the other end pops off with that same momentum. But this would not happen if we replaced the four identical balls with one ball which has four times the mass. The first ball would bounce back off the heavy ball without transferring all its energy.
I'm wondering if there are small gaps between the five balls or if they are touching when they hang at rest. If there are gaps, that would at least explain what happens when you pull back one ball. It slams into the second ball (the first one at rest), transferring all its momentum and energy, which in turn slams into the third ball, etc. But what about when you pull back two balls and release them? Would you expect two balls to transfer all their energy and momentum to the first ball at rest. That would seem to violate conservation of momentum and energy. But I think that in reality the two balls do transfer all their momentum and energy to the remaining three balls (whether or not it is transferred to each one successively, I don't know) . And somehow two balls pop off the other end with the same momentum the incoming two had.
I know this
satisfies the conditions of conservation of momentum and energy, but it doesn't seem like the only possible result that could satisfy those conditions. So how is the momentum and energy communicated from one end to the other?
