When train passes a moving object in the opposite direction
Let length of train = l meters and speed of train = x km/hr
Speed of the object = y km/hr and relative speed = (x + y) km/hr
Then, time taken by the train to pass the moving object = l meters/(x + y) km/hr
Now we will learn to calculate when train passes a moving object in the opposite direction.
A train 165 m long is running at the speed of 60 km/hr. In what time will it pass a man who is running at the speed of 6 km/hr in the opposite direction in which the train is moving?
Man moving in the opposite direction in which the train is moving.
Speed of train relative to the man = (60 + 6) km/hr
= 66 km/hr
= 66 × 5/18 m/sec
= 55/3 m/sec
Time taken by the train to cross a man = length of train/speed of train relative to man
= 165 m/(55/3) m/sec
= (165 × 3/55) sec
= 9 sec