When train passes a moving object in the same 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 same 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 same direction in which the train is moving?
Man moving in the same direction of the train
Speed of train relative to the man = (60 – 6) km/hr
= 54 km/hr
= (54 × 5/18) m/sec
= 15 m/sec
Time taken by the train to cross a man = distance/speed
= length of train/speed of train relative to man
= 165 m/15 m/sec
= 11 sec