How long will a 150m long train running at a speed of 60kmph take to cross a bridge of 300m
Answers
Answer:
27 seconds.
Let's think about the last carriage of the train.
When the front of the train reaches the bridge the last carriage still has 150 metres to go before reaching the same point.
The train has to travel 300 + 150 metres = 450 metres before the last carriage clears the bridge.
The standard units for speed are metres per second, so I'm going to convert the speed from km per hour into metres per second.
60 km in one hour = 60,000 m in one hour = 1000 m in one min = 1000 metres every 60 seconds = 100 metres every 6 seconds = 50 m every 3 seconds.
The train has to travel 450 metres at a speed of 100 metres every 6 seconds.
The train travels
50 m in 3 seconds
100 m in 6 seconds
200 m in 12 seconds
400 m in 24 seconds
450 m in 27 seconds - which is the time the train takes to clear the bridge.
This is what we had to show.
(Q.E.D.)
Answer:
the train cross the bridge when he cross the distance of bridge and the length of his own
total distance is (150+300)m=450m
time required 3600×450/60000sec
=27sec