Question

A sound wave traveling at 342 m/s is emitted by the foghorn of a tugboat. an echo is heard 3.20 s later. how far away is the reflecting object? answer in units of m.

Answer 1

Let's call L the distance between the tugboat and the reflecting object. The sound wave travels from the tugboat to the reflecting object, and then back again to the tugboat, in a total time of t=3.20 s. This means that the distance covered during this time is S=2L.

The sound wave moves by uniform motion, with velocity v=342 m/s, so we can use the basic relationship between space and time for a uniform motion:

`S=vt = (342 m/s)(3.20 s)=1094.4 m`

And so the distance L between the tugboat and the reflecting object is

`L= (S)/(2)= (1094.4 m)/(2)=547.2 m`