Question

Two trains are each 75m long moving parallel towards each other at speeds 10m/s and 15m/s respectively. At what time will they pass each other?

Answer 1

Given:-

• Length of the train = 75m

• Initial velocity of 1st train = 10m/s

• Initial velocity of 2nd train = 15m/s

To Find:-

• The Time they will pass each other.

Formulae used:-

• Time = Distance/speed.

Now,

As both trains are moving in opposite direction, the relative speed of train with respect to each other will be ,

→ v = 10 + 15 → 25m/s

→ Sum of the length of train = Distance Covered

→ 75 + 75 = 150

→ 150m

Therefore,

→ Time they will meet = $\rm{\dfrac{Distance}{speed}}$

→ $\rm{\dfrac{150}{25}}$

→ $\rm{ 6s }$

Hence, After 6 seconds they will Pass each other.

Answer 2

Answer:

$\underline{Given:}$

Both trains have same length of 75 m.

☆ It is moving parallel towards each other means they are travelling in opposite direction. ☆

Velocity of first train = 10 m/s

Velocity of second train = 15 m/s

To find:

The time they will pass each other.

Solution:

Distance covered by both the trains = 75 + 75 = 150 m. (since length of both the trains is 75 m)

As the trains are moving in opposite direction, its net relative velocity = 15 – (–10) = 15 + 10

= 25 m/s

Time taken = Distance/speed

= 150/25 = 6 s

Therefore both the trains will take 6 s to pass each other.