Question

Chris and Desiree are resting on an offshore raft after a swim. They estimate that 3.0 m separates the trough from the adjacent crest of each surface wave on the lake. They count 12 crests that pass by the raft in 20.0 s. How fast are the waves moving?

Answer 1

l = 3.0 m N =12 crests t = 20 s Speed = 2 l N / t = 2 X 3 m X 12 / 20 s =3.6 m/s