Density and Specific Gravity

Density is the mass per unit volume of a substance:

$\rho = \frac{m}{V}$

where $m$ is mass in kilograms and $V$ is volume in cubic metres. The SI unit of density is kg/m³.

Common Densities

Specific Gravity

Specific gravity (SG) is the dimensionless ratio of a substance's density to that of pure water at standard conditions ($\rho_{\text{water}} = 1000\,\text{kg/m}^3$):

$SG = \frac{\rho}{\rho_{\text{water}}}$

A specific gravity greater than 1 means the substance is denser than water and will sink; less than 1 means it will float.

Examples

Your Task

Implement density(mass, volume) that returns density in kg/m³, and specific_gravity(rho) that returns the dimensionless specific gravity relative to water.