Question

200 meter long train traveling by 60 km/h In how many time it will take to cross a pole?​

Answer 1

ans :

For answering these types of questions just consider 2–3 points

Firstly to cross the pole train has to cover its whole length

So total distance covered = length of the train

Second point is you have to see the units are same or not

Here distance is in meter and speed is in km/hr and you have to find time in sec.

So for that make all the units same.

Speed of train = 60km/hr

= 60*(5/18) simple way of changing km/hr to m/sec

Now the formula

Speed = distance / time

60*(5/18) = 200/time

300/18 = 200/time

time = 200*18/300

time =12 sec

Train will cross pole in 12 sec.

Its a simple math. We know the Universal formula of

Distance = Speed * Time (Formula 1)

Here, the distance is 200 metres and speed is 60 km/h, which we require in metre per second. So we need to convert our speed into m/s. Just multiply our speed with 5/18 (1000 (metre) / 60 (minute) * 60 (second)).

Speed = (60 * 5)/18 = 16.66 metres per second (round off to two decimal places)

Distance = 200 metres

Back to Formula 1

Distance = Speed * Time => Time = Distance / Speed

Time = 200 / 16.66 = 12 seconds approx.

Let us consider that the end point has to travel 200 m so that the train will cross the pole ,

So velocity of end point = velocity of train = 60 km/h

= 60x1000/60x60 m/s

=60x5/18 m/s = 50/3 m/s

Now v=s/t

So, 50/3=200/t

1/3=4/t

answer : t=12 secound