Train wrecks and momentum in the movies

When it comes to big things, it’s hard to get momentum right. We don’t have much experience with truly massive things moving quickly and unpredictably. Airplanes, trucks, and trains in normal circumstances aren’t surprising. But here’s a video of a train wreck during a tornado (nobody gets hurt). Watch through to the end to see Old Man Momentum get his due.

In old movies, they had to substitute small models for the real thing, so the physics were all wrong. Watch this video of the steamboat in the African Queen going over a waterfall. It’s clear the boat in the waterfall is about two feet long. With computer simulations and graphics, they can do much better these days. Here’s a clip from The Incredibles that involves a van speeding through traffic. Since they aren’t using a mechanical model, they can get the physics right, or close enough for a cartoon fantasy world.