Why does doubling your speed quadruple the crash, not double it? A 2011 physics thread still nails it (physics.stackexchange.com)
The work-distance argument carries it: force times distance equals energy, and a faster object travels farther under the same braking force, so the energy isn't 2x but 4x. A reader's two-cars puzzle turns it into a gut-level result.
The thread also surfaces the honest discomfort — one accomplished programmer admits physics' ‘obvious’ cause-and-effect steps have never clicked for him, and asks if he's alone. He isn't.
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