Question

1. Two trains, each 50 m long are travelling in opposite
directions with velocities 10 m/s and 15 m/s. The
time of crossing is?
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Answer 1

Question

Two trains each 50 m long are travelling in opposite directions towards each other with velocities 10 m/s and 15 m/s. The time of cross each other is?

Answer

Given -

Length of each train = $\rm 50 m$

Velocity of 1st train = $\rm v_1 = 10 m/s$

Velocity of 2nd train = $\rm v_2 = 15 m/s$

To find -

Time taken to cross the train - T

Solution -

The time of crossing is the time taken by 1 train to start from 2nd train starting and cross the 2nd train's end.

So the velocity of approach

$\rm = v_1 + v_2$

$\rm = 10 m/s + 15 m/s$

$\rm = 25 m/s$

The train are crossing each other ,so the total length

$\rm = 50 + 50$

$\rm = 100 m$

We know -

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

$\rm Time = \frac{\cancel 100}{\cancel 25}$

$\rm Time = 4sec$

Time taken to cross each other = 4 sec