Question

An observer sits in a boat watching wave fronts move past the boat. The distance between successive wave crests is 0.80 m, and they are moving at 2.2 m / s. What is the wavelength of these waves? 1.6 m 2.2 m 0.80 m What is the frequency of these waves? 0.36 Hz 2.8 Hz 0.80 Hz What is the period of these waves? 0.80 s 0.36 s 2.8 s

Answer 1

Using the wavelength expressions, such as the distance between two peaks of a wave, that of the frequency as a function of the speed and the wavelength, such as the period inversely proportional to the frequency we have to for the first question

the wavelength is the distance between the two ridges that is

$\lambda = 0.8m$

For the second question the frequency is determined as the rate of change of the velocity versus the wavelength, that is

$f = \frac{v}{\lambda}$

$f = \frac{2.2}{0.8}$

$f= 2.75Hz \approx 2.8Hz$

For the third question the period is inversely proportional to the frequency, therefore

$T = \frac{1}{f}$

$T = \frac{1}{2.8}$

$T = 0.36s$