# Hydrostatic Weighting

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Hydrostatic weighting, abbreviated as $$\rho_b$$, also called underwater weight, is how you can determine the average density of any object without nead for volume or measuring the mass per unit volume.

## Hydrostatic weighting formula

 $$\large{ \rho_b = \rho_w \; \frac { W_b } { W_b \;-\; W_{im} } }$$

### Where:

 Units English Metric $$\large{ \rho_b }$$  (Greek symbol rho) = density of body $$\large{\frac{lbm}{ft^3}}$$ $$\large{\frac{kg}{m^3}}$$ $$\large{ \rho_w }$$  (Greek symbol rho) = density of water $$\large{\frac{lbm}{ft^3}}$$ $$\large{\frac{kg}{m^3}}$$ $$\large{ W_b }$$ = weight of body $$\large{lbf}$$ $$\large{N}$$ $$\large{ W_{im} }$$ = weight of immersed body $$\large{lbf}$$ $$\large{N}$$

Tags: Soil Equations