Question
350 metre long train βAβ is running with a speed of
43.2 km/hr. Train βBβ which is 387 metre long is running with a speed of 90 km/h in opposite direction of train βAβ. For how much time, the smaller train is completely obscured by the larger train when they cross each other?Solution
Length of smaller train = 350 metre Speed of smaller train = 43.2 Γ (5/18) = 12 m/s Length of bigger train = 387 metres Speed of bigger train = 90 Γ (5/18) = 25 m/s Since, the smaller train is completely obscured by larger train, therefore, extra length of larger train = 387 β 350 = 37 metres Relative speed of trains βAβ and βB β= 12 + 25 = 37 m/s (Since, the trains are running in opposite direction) Required time = 37/37 = 1 second
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