Talk:Pressure-gradient force

Factual error: Pressure
The page states that pressure is a force per mass. Pressure is a measurement of force per area, is it not? Nschoem 01:13, 2 May 2008 (UTC)

Hey - it's actually NEGATIVE 1/rho * grad P --- pressure pushed in the opposite direction of the gradient (from high to low pressure, not the other way around)..... I fixed the error... (this is also in the Stull book referenced here) Here's the math:

$$ F = dP \cdot dA = (P_o - P_{o+dz}) \cdot dA = \frac{-dP}{dz} dz \cdot dA$$

$$\frac{-dP}{dz} dz \cdot dA = \rho \cdot dA \cdot dz \cdot a$$

$$\frac{-dP}{dz} = \rho \cdot a$$

-yano, 5/11/14

This concept is not restricted to air masses and earth-atmosphere effects. This page is linked in Hydrostatic equilibrium, the balance of gravitational effects with pressure gradient (i.e. why the sun is a relatively constant shape and size) Longillo (talk) 19:10, 20 January 2010 (UTC)

Conceptual Assumption
This article assumes that the force acting on the gas is only acting on the gas, and so the acceleration can be substituted using F=m*a. However this is only true for a very small amount of cases. It's a little misleading, even if it is true in some cases, to state the formula directly as this equation. Just saying.

Jondoge (talk) 12:58, 30 September 2014 (UTC)