a man is running with a speed of 12km/hr opposite direction of the train(speed of train is 60 km/hr) and the train crosses the man in 18 sec find the time taken by the train to cross a. 640 metre long tunnel
Answers
Answer:
MATHS
It takes 15 seconds for a train travelling at 60 km/hr to cross entirely another train half its length and travelling in opposite
The time taken by the train to cross a 640 meter long tunnel is 50 second.
Given:
Speed of man = 12kmph
Speed of train = 60 kmph
Time taken by train to cross the man = 18 sec
To find:
Time taken by train to cross a 540 m long tunnel
Solution:
First relative speed will be calculated to find out the total distance covered
As the other entity is a man, the total distance covered will be equal to the length of train
Relative speed is equal to sum of both speeds when the two things are in opposite direction
Relative speed = Speed of man + Speed of train
= 12 + 60
72 km/h = 72 * 5/18 m/s
= 4 * 5 = 20m/s
Total distance covered = Relative speed * Time taken
= 20 * 18 = 360 m
Length of train = distance covered = 360 m
Now, to calculate time taken by train to cross tunnel, both the distances have to be added
Total distance = length of train + length of tunnel
= 360 + 640
= 1000m
Time = Distance / speed of train
= 1000/20 = 50 sec
The time taken by the train to cross a 640 meter long tunnel is 50 second.
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