Question

How long will sound take to travel in (a) an iron rail and (b) air, both 3-3 km in length ? Take speed of sound in air to be 330 m $s^{-1}$ and in iron to be 5280 m $s^{-1}$.

Answer 1

(a) speed = $\frac{distance}{time}$
time =$\frac{distance}{speed}=\frac{3.3\times 1000}{5280}=0.625s.$
(b) time =$\frac{distance}{speed}=3.3\times \frac{1000}{330}=10s$