A man standing on the seashore determined that the distance between successive wave crests is 8 m.

A man standing on the seashore determined that the distance between successive wave crests is 8 m. In addition, he calculated that 24 wave crests passed by him in 1 minute. Determine the speed of propagation of the wave.

Given:

l = 8 meters – distance between successive wave crests (wavelength);

n = 24 – the number of waves passing by the observer during the time interval t;

t = 1 minute = 60 seconds – time span.

It is required to determine u (meter per second) – the speed of wave propagation.

Let’s determine the frequency of the wave:

v = n / t = 24/60 = 0.4 Hertz (second-1).

Then, to calculate the speed of wave propagation, you need to use the following formula:

u = l * v = 8 * 0.4 = 3.2 meters per second.

Answer: the wave propagation speed is 3.2 m / s.