The time-derivative of this quantity balances the divergence of its flux in fluid continuity equations.
In polytropic equations, the pressure is given as proportional to this quantity raised to some power, while the virial expansion writes the pressure over the temperature in terms of powers of this quantity. In cosmology, the quantity "3 times the square of the Hubble constant over quantity 8 pi times the gravitational constant," is known as the "critical" type of this quantity. The time-derivative of this quantity balances the divergence of its flux in fluid continuity equations. This quantity appears multiplied by both the square of the velocity and the gravitational acceleration times the height as a counterbalance to the pressure in Bernoulli's equation. Multiplying the volume and gravitational acceleration in the expression for buoyant force, for 10 points, identify this term which denotes how much of something there is per unit volume.
In polytropic equations, the pressure is given as proportional to this quantity raised to some power, while the virial expansion writes the pressure over the temperature in terms of powers of this quantity.
density