Core: The braking-distance rule of thumb: (speed:10)² : 2
The formula on p.126 has two steps: first divide speed by 10 and square it, then divide that result by 2. At 130 km/h: (13 x 13) : 2 = 84.50 m. At 50 km/h: (5 x 5) : 2 = 12.50 m. Braking distance is not the same as stopping distance. Stopping distance = reaction distance + braking distance. At 50 km/h that is 13.75 m (reaction distance) + 12.50 m (braking distance) = 26.25 m total — almost double the braking distance alone, because the reaction distance is added on top. The ratio stays quadratic, even without the :2 mistake: drive 2x as fast, and your braking distance becomes 4x as long. At 40 km/h braking distance is 8.00 m; at 80 km/h (2x as fast) it is 32.00 m — exactly 4x.
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- Challenge: The braking-distance rule of thumb: (speed:10)² : 2
- The model: The braking-distance rule of thumb: (speed:10)² : 2
- Why it matters: The braking-distance rule of thumb: (speed:10)² : 2
- Active recall: The braking-distance rule of thumb: (speed:10)² : 2
- Teach back: The braking-distance rule of thumb: (speed:10)² : 2
- Memory hook: The braking-distance rule of thumb: (speed:10)² : 2