Question

A train 110m long moving with a velocity of 45km per hour. Find the time it will take to cross a bridge of 1 km long?

Answer 1

To solve your question:

You need to convert each unit to its standard form, so:

V = 45Km/hr = 12.5m/s

S = 1km = 1000m

t = ?

Solution

=> V = S÷t

=> 12.5 = 1000÷t

=> t = 1000÷ 12.5

=> t = 80 s

So it will take 80 seconds for a train moving at 12.5 meters every second to cross a kilometer long bridge.

However,

The question states the train is 110 meters long.

This means the last point on the train has an extra 110 meters to cover.

So it becomes:

t = 1110 ÷12.5

t = 88.8 s.

So the time it takes a train 110m long, moving at 12.5km/hr to cover 1km is 88.8 seconds