Question

A fisherman passes the time by counting waves passing under his boat. He notices that his boat rises and falls 8 times in 65 seconds. He counts 6 wave crests between his boat and a buoy located 54 m away. What is the speed of the water waves?

Answer 1

$v=\frac s t,\\ \nu=\frac {n}{t_1},\\ t=\frac {k}{\nu},\\ v=\frac{sn}{kt_1},\\ v=\frac{54\cdot 8}{6\cdot 65}\approx 1.1~\frac{\text{m}}{\text{s}}.$