Question

A train 50 m long passes over a bridge at a velocity of 36 km/h. If it takes 35 s to cross the bridge, the length of the bridge will be

• A. 100 m
• B. 200 m
• C. 250 m
• D. 300 m

Answer 1

The correct option is D 300 m

Let the length of the bridge be $L$.
Total distance covered by the engine to cross the bridge $d=50+L$
Speed of train $v=36km/h=36\times \frac{5}{18}=10m/s$
Time taken $t=35s$
Using $d=vt$
Or $L+50=10\times 35$
$⟹L=300m$