A train `100 m` long moving on a straight level track passes a pole in `5 s`. Find (a) the speed of the train (b) the time it will take to cross a bridge `500 m` long.

Answer

(a) `20 m//s` , (b) `30s`

Explanation

(a) velocity `= ("distance travelled")/("time taken")` , i.e ., `v = ( 100 m)/( 5 s) = 20 m//s`
(b) length of bridge `= 500 m`, length of train `= 100 m`
In crossing the bridge, distance moved, `s = 500 + 100 = 600 m` ,
time , `t = (s)/( v) = (600)/(20) = 30s`