Question

A person is listening with his ear against the rail for an on coming train . when the train is 1.65 km away, how long will it take him to hear the sound through
the rails ? Round off to 2 decimal places,
(the speed of sound in steel is 5200 m/s)​

Answer 1

Given:

A person is listening with his ear against the rail for an on coming train ,when the train is 1.65 km away.

To find:

How long will it take him to hear the sound through the rails ?

Calculation:

So, the time taken for sound to travel the specified distance into the ears of the listener can be calculated by dividing the distance with the the speed of sound through steel.

$\sf \therefore \: time = \dfrac{distance}{speed}$

$\sf \implies \: time = \dfrac{1.65 \: km}{5200 \: m/s}$

$\sf \implies \: time = \dfrac{1650 \: m}{5200 \: m/s}$

$\sf \implies \: time = 0.317 \: s$

So, it will take 0.317 seconds for the sound to reach the listerner's ears through steel.