Question
Two trains A and B of length 400 m each are moving on two parallel tracks with a uniform speed of 72 km/hr in the same direction, with A ahead of B. The driver of B decides to overtake A and accelerates by 1 m/s2. If after 50 s, the guard of B just brushes past the driver of A, what was the original distance between them?
Solution
Here,
Velocity of train A, 
Velocity of train B, 
Acceleration of train A, 
Acceleration of train B, 
Let initially A be ahead of B by a distance d. Let SB and SA be the distances travelled by trains B and A respectively in 50s.
As at t = 50 s the position of both the trains is same.
Therefore,
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Now,
∴ original distance between them is, 
