What happens to a vehicle's stopping distance when speed doubles, all else being equal?

Pick an answer

1. Stopping distance stays about the same regardless of speed
2. Stopping distance increases by much more than double, since braking distance grows with the square of speed
3. Stopping distance exactly doubles as well
4. Stopping distance only doubles along with speed, not increases by more than that, a detail that's easy to miss with equal

Correct!

Not quite. The correct answer is highlighted.