Velocity of parrot $v_{P}=-5 m s ^{-1}$ Relative velocity of parrot with respect to train
$=v_{P}-v_{T}=\left(-5 ms ^{-1}\right)-\left(+10 ms ^{-1}\right)=-15 m s ^{-1}$
i.e. parrot appears to move with a speed of $15 m s ^{-1}$ from north to south
$\therefore$ Time taken by parrot to cross the train
$=\frac{150 m }{15 ms ^{-1}}=10 s$
(જ્યાં $v$ વેગ છે)
કારણ: નિયમિત ગતિમાં જેમ સમય વીતે તેમ પદાર્થનો વેગ વધતો જાય.