Question

A train of 150 m in length is going towards the north direction at a speed of 10.5 m/s. A parrot flies at a speed of 4.5 m/s towards the south direction parallel to the railway track. What is the time taken by the parrot to cross the train?

Answer 1

Step 1:GIven data:

The velocity of the train, $v_1=10.5m/s.$

The velocity of the parrot, $v_2=4.5m/s.$

Length of the train = 150 m.

Let, the time taken by the parrot to cross the train is t sec.

Step 2:Finding relative velocity(v):

Now, the relative velocity(v) of the parrot is,

$$\begin{gathered} v=v_1-\left(-v_2\right). \\ orv=v_1+v_2=10.5+4.5=15m/s. \\ orv=15m/s. \end{gathered}$$

(since the train and the parrot are moving opposite to each other.)

Step 3:Finding the time :

Taking the formulae,

$Time=\frac{Distance}{Velocity}.$

Now,

$$\begin{gathered} Time=\frac{Distance}{Velocity}=\frac{150}{15}=10seconds. \\ ort=10seconds. \end{gathered}$$

Therefore, the time taken by the parrot to cross the train is 10 seconds.