Question

A train 210m long is running at a speed of 45km/hr . It crosses a a bridge in 30 secs . Find the length of the bridge
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Answer 1

Answer:

165 m is the length of bridge

hope it helps

Answer 2

Answer:

A train 210m long is running at a speed of 45km/h. It crosses a bridge in 30 secs. The length of the bridge is $165m$

​Step-by-step explanation:

• The speed (V) of a body is the total distance(d) covered by it divided by the time taken (t) to cover the distance

        $V=d/t$

From the question,

length of the train $l=210m$

let the length of the bridge be x

time taken to cross the bridge  $t=30s$

speed of the train $V=45km/h=45*5/18=12.5m/s$

but speed is the total distance divided by time

total distance =length of the train +length of the bridge

⇒

$V=x+l/t$

$12.5=\frac{x+210}{30}$

$375=x+210\\x=375-210=165m$

so the length of the bridge $x=165m$