Question

Train with 90 km/h crosses a bridge in 36 seconds. another train 100 metres shorter crosses the same bridge at 45 km/h. what is the time taken by the second train to cross the bridge ? 61 seconds 63 seconds 62 seconds 64 seconds

Answer 1

In first train
u=90km/h
=90×5/18 m/s
=20 m/s
t=36 seconds

In second train
u=45 km/h
=45×5/18 m/s
=12.5 m/s
The second train is two times shorter than the first train..
If the train is 2 times shorter then the time will be two times greater than the first train.

time taken by the second train= 36 × 2
=62 seconds