A person fishing from a pier observes that 5 wave crests pass by in 8.1 s and estimates the distance between two successive crests to be 3.8 m. The timing starts with the first wave crest and ends with the last. What is the speed of the wave

Speed of the wave is 1.406 m/s.

Explanation:

Crest is define as the maximum displacement of particle in a wave. A single wave is form between two successive crest.

As shown in the figure, there are 4 crest, so 3 waves are formed.

According to the problem, 5 wave crest are form in time 8.1 s. Hence the number of waves formed is 4.

Frequency of wave, f = = = 0.37 Hz

Wavelength of wave, λ = 3.8 m

Speed of the wave = λ x f = 3.8 x 0.37 = 1.406 m/s