Answer:
7.1 sec
Explanation:
The speed of sound in copper is
[tex]v=3500 m/s[/tex]
The lenght of the rod, which is the distance the sound wave should travel, is
[tex]S=25 km=25,000 m[/tex]
We know that the relationship between distance traveled, speed and time taken is:
[tex]v=\frac{S}{t}[/tex]
where t is the time taken. By re-arranging the equation and using the data of the problem, we find the time the sound wave takes to travel through the rod:
[tex]t=\frac{S}{v}=\frac{25,000 m}{3500 m/s}=7.1 s[/tex]
