Question

A person driving a car with a speed 72 km/h, suddenly sees a boy crossing the road . If the distance moved by a car, before the person applies brakes is 5m, the reaction time of the person is:

• A. 0.5 s
• B. 0.10 s
• C. 10 s
• D. 0.25 s

Answer 1

The correct option is D 0.25 s

$v=72km/hr=\frac{72\times 5}{18}=20m/s$

Time taken to cover the distance of 5m is:

$t=\frac{5}{20}=0.25sec$

This time is called Reaction time.