Question

Sumit was standing at the railway crossing when a train crossed him at a speed of 40km/h in 15 seconds , find the length of the train.

I need step by step explaination.​

Answer 1

Answer:

The length of train is 166.67m.

Step-by-step explanation:

Given,

• Speed - 40km/h
• Time - 15s

Firstly, we will convert speed unit into m/s.

1 km = 1000m

1 hr = 60 × 60sec

$speed = 40kmh \\ = \frac{40 \times 1000}{60 \times 60} \\ = 11.1111 {ms}^{ - 1}$

Now,

$speed = \frac{distance}{time} \\ 11.1111 = \frac{x}{15} \\ x = 166.67m$

The length of train is 166.67m.

Answer 2

Answer:

Sumit was standing at the railway crossing when a train crossed him at a speed of 40km/h in 15 seconds, the length of the train is $166.65m$

Step-by-step explanation:

• The speed $V$ is defined as the change in position $d$ (distance) with respect to the time taken $t$ to cover the distance, that is

            $V=d/t$

• Use the unit conversion $km/h=5/18m/s$

From the question, it is given that

speed of the train while crossing the boy is

$V=40km/h=40*5/18=11.11m/s$

time taken by the train to cross him $t=15s$

length of the train is equal to the distance traveled by it

⇒$d=Vt$

$d=15*11.11=166.65m$