Problem 1. Conservation debate. Two friends are having a friendly disagreement on the conservation of energy and momentum. "Conservation of energy and momentum are basic principles of physics. They both are always conserved!" says Emmy. "That's demonstrably false," says Aristotle. He picks up a rock and throws it against the wall. "See? The rock had forward momentum. Then, it hit the wall and had momentum back towards us. And then its momentum starting pointing downward until it stopped on the floor. Likewise, its energy was changing the whole time and eventually disappeared." How do you explain the conservation laws to your two friends? Explain your reasoning in several sentences as if they had both taken Physics 41 a few years ago but forgot all the details.