A driver reduces speed from 100 km/h to 50 km/h. By what factor does the braking distance change?
Answer and explanation
Correct answer: A. 0.25
- Step 1: Braking distance is proportional to the square of the speed. Step 2. Factor = (50 ÷ 100)² = 0.25. Answer: 0.25. Why not the others: 0.5 results from having forgotten to square the speed ratio. 0.125 results from having cubed the speed ratio. 1.25 results from having added one to the correct factor.
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