Question

A train blows its whistle as it enters a 50 m long tunnel. What is the time delay heard by a person at the other end of the tunnel between the sound of the train's whistle through the rails and through the air? Assume that the speed of sound in the air and steel are 342 m/s and 5960 m/s respectively.

I probably know how to answer this but I just don't understand what the question is saying and what I'm supposed to do.

Answer 1

So,the problem is trying to tell you that you can hear the sound twice. First is through the air, and the second is through the railings. Sounds travel faster through a medium. So, the sound through the rails would reach you first than the sound through the air. Find the time difference.

Time for Sound through air = 50 m / 342m/s = 0.146 s
Time for Sound through steel = 50 m / 5960m/s = 0.00839 s
Time difference = 0.146 - 0.00839 = 0.136 s