A driver travelling at 54 km/h needs 2 s to react to a hazard. How far does the car travel before the driver starts to brake?
Answer and explanation
Correct answer: B. 30 m
- Step 1: Speed in m/s = 54 ÷ 3.6 = 15 m/s. Step 2. Distance = 15 × 2 = 30 m. Answer: 30 m. Why not the others: 108 m results from having treated km/h as m/s. 15 m results from having halved the reaction time. 60 m results from having doubled the reaction time.
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