Multiple choice

An automobile travelling with a speed of 60 km/hr can stop within a distance of 20 m. If a car travels twice as fast, i.e. 120 km/hr, then the automobile will stop within a distance of

  1. 20 m

  2. 40 m

  3. 60 m

  4. 80 m
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Stopping distance is proportional to the square of the velocity (d proportional to v^2). If speed doubles (v becomes 2v), the distance becomes 2^2 = 4 times the original distance. Thus, 20 m * 4 = 80 m.

AI explanation

The stopping distance formula is proportional to the square of the velocity, assuming the same deceleration. When the speed doubles from 60 kilometers per hour to 120 kilometers per hour, the stopping distance becomes two squared times the original distance. Therefore, the new stopping distance is 4 multiplied by 20 meters, resulting in 80 meters.

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