Question

A geographer about to dig out crude oil sent a note of velocity 340 m/s into the earth crust which was reflected by two layers of the crust. If he had two echoes of the note after 2.3s and 4.4s respectively, calculate the distance between the two layers.

Answer 1

By definiton, the distance travelled by the sound is:

$$d = v\Delta t$$

where $\Delta t = 4.4s-2.3s = 2.1s$ is the time interval, and $v = 340m/s$ is the speed of sound. Thus, obtain:

$$d = 340m/s\cdot 2.1s = 714 m$$

Answer. 714 m.