collisions

This was a good weekend. Class day was fun, went to the beach, caught up on sleep, and ate a lot of food, but best of all, I got my fat boot off so i don't need my crutches. And for the record, Doc, I got my cast off on wednesday, went to class day, and I actually didn't screw up my ankle like you said i would hahaha. Anyway, this weekend my cousins from Washington came to visit and I got to hang out with my two nephews, Tyler and Tanner. They love cars and they especially like to play the ds game mario kart. They had their small collection of miniature race cars and we were pushing them around, when a two of them collided head-on and I thought, "Oh shnap! Elastic collisions and the conservation of momentum!" We were pushing them on a smooth wooden floor so there wasn't much friction but this is not quite an elastic collision because the total kinetic energy was not conserved. However, if I only include the two cars in the system, momentum is constant the collision is an action-reaction force with equal magnitude. The velocity of one is positive but the velocity of the other car is negative so the momentum and net force on the system is 0. We also played tons of mario kart and there were many two-dimensional collisions. These collisions happened super fast and they were in the game, so there is really no way to calculate the degrees and stuff. It's amazing how physics just pops up everyday!