A driver applies the brakes on seeing traffic signal 400 m ahead. At the time of applying the brakes vehicle was moving with 15 ms-1 and retarding with 0.3 ms-2. The distance of vehicle after 1 min from the traffic light:

Q. A driver applies the brakes on seeing traffic signal 400 m ahead. At the time of applying the brakes vehicle was moving with 15 ms-1 and retarding with 0.3 ms-2. The distance of vehicle after 1 min from the traffic light:

(A)  25 m

(B)  375 m

(C)  360 m

(D)  40 m

Solution : The maximum distance covered by the vehicle before coming to rest

s = v2/2a

= (15)2/2×0.3

= 375 m

The corresponding time  = t = v/a

= 15/0.3 = 50 sec

Therefore after 50 seconds, the distance covered by the vehicle = 375 m from the instant of beginning of braking.

The distance of the vehicle from the traffic after one minute  = (400 – 375) m = 25 m

Ans: (A)

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