Question

dolphins of the open ocean are classified as type ii odontocetes (toothed whales). these animals use ultrasonic “clicks” with a frequency of about 55 khz to navigate and find prey. suppose a dolphin sends out a series of clicks that are reflected back from the bottom of the ocean 75 m below. how much time elapses before the dolphin hears the echoes of the clicks? (the speed of sound in seawater is approximately 1530 m/s).

a. 0.098 s
b. 0.074 s
c. 0.033 s
d. 0.049 s
e. 0.012 s

Explanation:

Step1: Determine the distance traveled by sound

The sound travels to the bottom of the ocean and back. So the total distance $d$ is $d = 2\times75\ m=150\ m$.

Step2: Use the speed - time formula

The speed - time formula is $v=\frac{d}{t}$, where $v$ is speed, $d$ is distance and $t$ is time. We can re - arrange it to solve for time $t=\frac{d}{v}$. Given $v = 1530\ m/s$ and $d = 150\ m$. Then $t=\frac{150}{1530}\ s\approx0.098\ s$.

Answer:

A. 0.098 s