Question

A train of $150$m length is going towards north direction at a speed of $10$m/s. A parrot flies a speed of $5$m/s towards south direction parallel to the railway track, the time taken by the parrot to cross the train is equal to.

Answer 1

Considering direction south as positive, relative velocity of parrot with respect to train = 5 - ( - 10 ) m/s = 5 + 10 = 15 m/s

Hence time taken to cross the train = length/ relative velocity

= 150m ÷ 15m/s = 10 seconds.