Question

Annabelle is taking the Polar Express ALL the way to the North Pole! The Polar Express is 100 meters long and it takes 30 seconds to cross Santa’s 400m ice bridge. What speed is the train going at?(30,45,60,80km/h)

Answer 1

When the train reaches the bridge the nose of the locomotive has to travel 400 m to get from one end of the bridge to the other end.

Then the whole train is on the bridge so the nose of the locomotive has to go another 100m to drag the whole train off the bridge.

So the locomotive must travel 500 M for the whole train to cross the bridge.

500 m/ 30s. = 16-2/3 m/s = 60 km/hr.