A skipper on a boat notices wave crests passing his anchor chain every 9 s. He estimates the distance between wave crests to be 15 m. He also correctly estimates the speed of the waves. What is this speed?

Wavelenght* frequency= wave speed

remember that frequency here is 1wave/9sec or 1/9


To find the speed of the waves, we can use the formula:

wave speed = wavelength × frequency

In this case, we have the frequency of the waves, which is 1 wave every 9 seconds. So, the frequency is 1/9.

Now, we know the distance between wave crests, which is the wavelength. Given that the wavelength is estimated to be 15 meters, we can substitute these values into the formula:

wave speed = 15 meters × (1/9 waves/second)

Calculating the value:
wave speed = 15 meters × 1/9
wave speed = 15/9 meters/second
wave speed ≈ 1.67 meters/second

Therefore, the speed of the waves is approximately 1.67 meters per second.