Question

a train 100m long is to cross a river of Bridge length 800m what time will it take to cross the bridge? The train move with a constant velocity of 36 km per hour

Answer 1

time is distance divide by speed
$800 + 36$
22 sec

Answer 2

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

d = (100 + 800) m = 900 m

The speed of the train is,

v = 36 km/h = 36 × 5 / 18 = 10 m/s

Hence the time taken to cross the bridge is,

t = 900 / 10 = 90 s.