A liquid drop placed on a horizontal plane has a near spherical shape (slightly flattened due to gravity). Let $R$ be the radius of its largest horizontal section. A small disturbance causes the drop to vibrate with frequency $\nu$ about its equilibrium shape. By dimensional analysis the ratio $\nu^2$ can be (Here $\sigma$ is surface tension, $\rho$ is density, $g$ is acceleration due to gravity, and $k$ is arbitrary dimensionless constant):