question_answer 7)

Two trains A and B of length 400 m each are moving on two parallel tracks with a uniform speed of  in the same direction, with A ahead of B. The driver of B decides to overtake A and accelerates by . If after 50 s, the guard of B just brushes past the driver of A, what was the original distance between them ?  

Answer:

Let x be the distance between the driver of train A and the guard of train B. Initially, both trains are moving in the same direction with the same speed of . So relative velocity of B w.r.t. . Hence the train B needs to cover a distance with   As                            .