Question

A Boy throws a pebble into the center of the pond. A floating leaf near the waters edge oscillates ( moves up and down ) two complete cycles in one second as water waves move past the leaf. The waters wavelength is 10 meters. What is the waves velocity?

Answer 1

Wave speed = (wavelength) x (frequency)

= (10 m) x (2 / sec) = 20 m/s.

By the way . . .
The water doesn't move past the leaf. Only the wave does.