Physics Course/Motion/Periodic Motion/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
 * $$y(\theta) = r Sin \theta$$
 * $$x(\theta) = r Cos \theta$$

High Low Wave
Water wave moves in a direction that changes its amplitude sinusoidally
 * $$y(t) = r Sin \omega t $$
 * $$\omega = \frac{\lambda}{t} = \lambda f$$

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