The time taken by a 240m log train, traveling at a speed of 72km/hr to cross a pole is what?
Answers
Answer:
Given:
Speed of the train = 72 km/h
Length of the train = 240 m
Time to cross a tunnel = 1 minute
Concept used:
Distance = Speed × Time
km/h × 5/18 = m/sec
1 minute = 60 sec
Calculation:
Speed of the train = 72 km/h
⇒ 72 × 5/18 = 20 m/sec
Time to cross the tunnel = 60 sec
Let the length of the tunnel be L.
(240 + L)/20 = 60
⇒ (240 + L) = 60 × 20
⇒ 240 + L = 1200
⇒ L = 1200 – 240
⇒ L = 960
∴ The length of the tunnel is 960 m.
In context to question asked,
We have to determine the time taken by 240 m long train to cross the pole, if it is running with a speed of 72 Kmph.
So, for determining the time,
We will convert speed into m/sec.
So, we will get the speed in m/sec/ as -
So, as the speed of train is 20 m/sec.
So, when it cover the pole,
Then the expression for time period will be,
Hence, putting the value given in question in above formula,
We will get,
Hence, train will take 12 seconds to cross the pole.