Question

two trains each of length 50m, are approaching each other on parallel rails. their velocities are 10m/s and 15m/s .they will cross each other in

Answer 1

distance = 2*d  (here d =50m)

              =2*50 =100m

speed = 10+15=25m\s (since the approch each other from different direction)

therefore time= distance\speed

                         =100\25=4sec

Answer 2

Answer:

They will cross each other in 4 sec.

Explanation:

Given that,

Length of train = 50 m

Velocity of first train = 10 m/s

Velocity of second train = 15 m/s

The total distance $D= 2d = 2\times50=100\ m$

The velocity of second train relative to first train .

The relative speed is

$v= v_{s}-(-v_{f})$

$v=15+10=25\ m/s$

The speed is equal to the distance divided by the time.

So, The time is

$t = \dfrac{D}{v}$

Where, D = distance

t = time

v = relative speed

Put the value of D and v into the formula

$t =\dfrac{100}{25}$

$t = 4\ sec$

Hence, They will cross each other in 4 sec.