Question

a train 100 m long moving on a straight level pases a pole in 5 s find the time it will take to cross a bridge of 500 m long

Answer 1

Solution :

According to the given question , a train of 100m length moving on a straight level passes a pole in 5s.

Let us assume that the speed of the train is x m/s.

Speed = Distance/Time

> x = [ Length of train + width of pole]/Time

> x = 100/5 = 20 m/s.

So , we got to know that the speed of the train is 20 m/s.

Now we have to find the time it should take to cross a bridge of length 500m .

Total distance to be covered by the train :

> Length of train + length of bridge

> 100m + 500m

> 600 m .

Speed > 20 m/s .

Time taken to cover >> 600/20 >> 30s.

Answer - The train will take 30s to cross a bridge of length 500m .

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Answer 2

Distance covered by train in 5 seconds= 100m

Distance covered by train in 1second = 100/5 = 20m.

So Speed of the train is 20m/sec.

ii).

Distance = 500m

Speed = 20m/sec.

Time = ?

Speed = d/t

t = d/speed

Time = 500 ÷ 20

= 25 seconds.