# Physics Course/Motion/Periodic Motion/Wave

## Water Wave

### Concentric Circles

Concentric circles travels in a direction when there is a cobble drops on the water surface

$x^{2}+y^{2}=r^{2}$
$Tan\theta ={\frac {y}{x}}$

Which can be expressed as

$y(\theta )=rSin\theta$
$x(\theta )=rCos\theta$

### High Low Wave

Water wave moves in a direction that changes its amplitude sinusoidally

$y(t)=rSin\omega t$
$\omega ={\frac {\lambda }{t}}=\lambda f$

With

$\lambda$ : Wavelength . The distance between 2 crests (highest point)
$f$ : Frequency . frequency of time to complete a cycle