You are sitting in a stationary boat and your friend is sitting in another boat nearby. Ocean swells (long waves) are passing by. You notice that whenever you are at the crest of a wave (i.e. the crest is passing under you) your friend is at the crest of the next wave. The boats are 8 m apart. You time the waves and find that the time between the arrival of each crest is 4 s. What is the wavelength of the ocean swell?
What is the period of the swell?
What is the frequency of the swell?
How far does a crest travel in 4 s? What do you conclude is the speed of the waves?