A fisherman notices that wave crests pass the bow of his anchored boat every 4.0 s. He measures the distance between two crests to be 6.5 m. What is the wave speed in m/s?

1.625 m/s

Explanation:

The speed of a wave is expressed as

V = λf ... Equation 1

Where V = speed of wave, λ = wavelength, f = frequency of the wave.

Recall,

f = 1/T ... Equation 2

Where T = Period or time taken for the wave crest to pass the bow of the anchored boat

Given: T = 4.0 s.

Substitute into equation 2,

f = 1/4

f = 0.25 Hz.

Also given: λ = 6.5 m.

Again, substitute into equation 1,

V = 6.5 (0.25)

V = 1.625 m/s.

Hence the speed of the wave = 1.625 m/s