Question

A 100 m long train crosses a 10 m long bridge at a speed of 70 km/hr. How much time will it take to cross the bridge completely? help me please

Answer 1

So, first you would want to drop down to all the same units,
70kmh = 70000m/hr
Then you can think of the bridge as being 10m more that the train must travel, so you can add that and get 110 m for the distance needed to be traveled in time x and set your equation
\[x=110m / 70000m/hr\]
11/7000 hours or approx 0.001571 hours.
you can convert to seconds, or something if you prefer.

Answer 2

~five and a half seconds