Question

A train 100 m long travelling at 40 ms−1 overtakes another train 200 m long travelling at 30 ms−1. Find the time taken by the 1st train to pass the second train?​

Answer 1

EXPLANATION.

• GIVEN

A train 100 m long travelling at = 40 m/s

overtake another time 200 m long travelling

at = 30 m/s

Find the time taken by the 1st train

to the second train.

According to the question,

Let the length of 1st train = 100 m

Let the speed of first train = 40 m/s.

Let the length of 2nd train = 200 m

Let the speed of second train = 30 m/s

Relative velocity = V1 - V2

=> 40 - 30 = 10 m/s

total distance of the train to travel overtake

second train.

=> 200 + 100 = 300 m

=> Distance = Speed X Time

=> Time = Distance/speed

=> Time = 300 / 10

=> Time = 30 seconds.

Therefore,

the time taken by the 1st train to

pass the second train = 30 seconds.

Answer 2

✏ What is Given?

• A train 100 m long travelling at 40 ms-¹ overtakes another train 200 m long travelling at 30 ms-¹.

✏ What we need to Find?

• Time taken by the 1st train to pass the second train.

☑ Solution ☑

We know that,

Relative Velocity = V¹ - V²

So, Relative Velocity = 40 - 30 = 10m/s.

Now,

Total Distance = 200 + 100 = 300m.

Now, Calculating Time.

Time = Distance/Speed.

➣ Time = 300/10.

➣ Time = 30 seconds.

Hence, Time taken by the first train to pass the second train is 30 seconds.