Two trains A and B of length 400 m each are moving on two parallel tracks with uniform speed of 72 kmh-1 in the same direction with A ahead of B. The driver of B decides to overtake Aand accelerate by 1 ms-2. If after 50 s, the guard of B just passes the driver of A, what was the original distance between them?

Train A

Initial Velocity = UA = 72 kmh-1 = 20 ms-1


Time Taken = t = 50s


Acceleration = aA = 0 ms-2


Now, from the equations of motion, we know that,




m


Driver is at starting of Train A


Train B


Initial Velocity = UA = 72 kmh-1 = 20 ms-1 Time Taken = t = 50 s


Acceleration = aB = 1 ms-2


Now, from the equations of motion, we know that,




m


Guard is at the end of Train B


Now, length of both trains = 400 m + 400 m = 800 m


Now, Original distance between Train A and B is S, which can be obtained as given below:


S = 2250 m – 1000 m – 800 m


= 450 m


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