Question

A train 100m long is moving with a constant velocity of 60km/hr. Find the time it takes to cross the bridge 1km long?

Answer 1

1 km = 1000 m

total distance = 100 m + 1000m = 1100 m

speed = 60 km /hr = 60 x 5/18
= 16.66 m/s

time = distance / speed
= 1100 / 16.66
= 66.026 sec [ approx. ]

Answer 2

Total distance required for the train to cross the bridge is,

d = (100 + 1000) m = 1100 m

The speed of the train is,

v = 60 km/h = 60 × 5 / 18 = (50/3) m/s

Hence the time taken to cross the bridge is,

t = 1100 / (50/3) = 66 s.