On a foggy day two drivers spot each other when they are just 80 mts apart. They are travelling at 72 kmh^(-1)and 60 kmh^(-1), respectively . Both of them applied brakes retarding their cars at the rate of 5ms^(-2). Determine whether they avert collision or not .

On a foggy day two drivers spot each other when they are just 80 mts a

1.	On a foggy day two drivers spot each other when they are just 80 mts apart. They are travelling at 72 kmh^(-1)and 60 kmh^(-1), respectively . Both of them applied brakes retarding their cars at the rate of 5ms^(-2). Determine whether they avert collision or not .
Answer» Solution :For the FIRST car : u =` 72 kmh^(-1)` `(72 xx 1000)/(3600) = 20 ms^(-1) , v = 0 , a = - 5 ms^(-2)` As `v^(2) - u^(2) = 2as` `:. 0^(2) - 20^(2) = 2 (-5) s, = 10 s` Distance COVERED by first car , `s_(1) = 40 m,` For the second car : `u = 60 kmh^(-1) = (60 xx 5)/(18)` ` = (50)/(3) ms^(-1) , v = 0, a = - 5 ms^(-2)` As`v^(2) - u^(2) = 2as` `:. 0^(2) - ((50)/(3))^(2) = 2 (-5) s` Distance covered by second car, `s_(2) = (2500)/(9 xx 10) = 27 . 78` Total distance covered by the two cars `rArr s_(1) +s_(2) = 40 + 27 . 78 = 67 . 78 m ` As this distance is less than the initial distance (-80m) between the two cars,so the collision will be averted .