Question

A crest of a water wave travels 80 cm in 4 s. If
the distance between 2 successive crests is
4 mm, what is the frequency of the wave

Answer 1

we have distance and time we can get velocity by it

$v = d \div t$
$v = 80 \div 4$

we get v=20 cm/s

now to get frequency you should know the relation

between velcity and wavelength

frequency=velocity/wavelength

=20/4*10
=50hz