system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it that if two cars run into each other while both going 60mph the collision isn't equivalent to a 120mph crash?
gpt
That 60 mph crash is into a solid, unmovable wall, and all the energy is absorbed by 1 car. In the two cars colliding head on at 60mph each, each car delivers as much energy as the other, but also absorbs as much, so while the total energy in the collision might be double, it's also absorbed by double the number of cars, and each car absorbs the same as just 1 hitting a solid object.

When the cars have different masses, it changes, and something like a big rig at 60mph smoking a smart car at 60mph, head on, becomes much  more like a 120mph accident, for the smart car. On the other hand, the big rig won't see it as nearly a violent accident as it would had it struck a solid wall instead.

This has great implications in crash-test ratings. The Smart has great forward crash test rankings, thanks to it's high-tech and ultra-rigid body. But against something like an F-350...mass wins.