Q: A car is moving with a velocity of 40 m/s. the drivers sees a stationary truck ahead at a distance of 200 m. after some reaction time Δt the breaks are applied producing a (reaction) retardation of 8 m/s2. What is the maximum reaction time to avoid collision ?
Sol. The distance travelled by the car is 100 m
To avoid the clash, the remaining distance 200 – 100 = 100 m must be covered by the car with uniform velocity 40 m/s during the reaction time Δt.
100/(Δt) = 40
⇒ Δt = 2.5 s
The maximum reaction time Δt = 2.5 s