Question

The average time taken by a normal person to react to an emergency is one fifteenth of a second and is called the 'reaction time'. If a bus is moving with a velocity of 60 km/h and its driver sees a child running across the road, how much distance would the bus had moved before he could press the brakes? The reaction time of the people increases when they are intoxicated. How much distance had the bus moved if the reaction time of the driver were 1/2 s under the influence of alcohol?

Answer 1

Bus is moving with initial velocity of u = 60 km/hr.
60 km/hr = ( 60 X 1000)/3600 = u = 16.66 ms^-1.
Reaction time = t =1/15 sec.
Distance would the bus had moved before pressing the bus would be = u X t.
S = 16.66 X 1/15 = 1.1 m.
Now if the driver is intoxiacated then reaction time would be t = 1/2 seconds.
So S becomes S = u X t = 16.66 X 1/2 = 8.33m.