Consider Newton's cradle. Hopefully your Section Coach will be able to bring the demo to the class, but you can also play with this simulation. You've probably seen how when you drop one ball, the one in the other end bounces off, and the ones in the middle stay still. Why does this happen? Is energy conserved? Is momentum conserved? If so, why and when? Now release two balls. You'll probably see how the two on the other end bounce off. Why doesn't just one bounce off with twice the speed? Now release all except onewhat happens? Why does this and not anything different happen