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Question
When we put our ear to a railway line, we can hear the sound of an approaching train even when the train is far off but its sound cannot be heard through the air. Why?
Solution
Sound travels about 15 times faster in iron or steel than in air. We can hear the sound of an approaching train by putting our ear to the railway line made of iron or steel even when the train is far away because the sound produced by the motion of train’s wheels over the railway line is carried away quickly by the steel rails than in air.
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