#### Hydrostatic equilibrium equation

## What is the hydrostatic equation?

The equation is: dP/dz = – density*gravity. Written in English, this is the change in pressure with the change in height is equal to the average density of the air times the gravitational constant.

## What is meant by hydrostatic equilibrium?

In fluid mechanics, hydrostatic equilibrium or hydrostatic balance (also known as hydrostasy) is the condition of a fluid or plastic solid at rest. This occurs when external forces such as gravity are balanced by a pressure-gradient force.

## When the atmosphere is in hydrostatic equilibrium what two forces are in balance?

The direction of the gravitational force points toward the Earth’s core (downward from the surface) and thus gravity is a force on the air acting to push it toward the ground. These two forces when equally balanced is termed “hydrostatic balance”.

## How do we know the sun is in hydrostatic equilibrium?

When the force due to pressure exactly balances the force due to gravity, a system is in hydrostatic equilibrium. The Sun’s hydrostatic equilibrium is stable and self-regulating; if you tossed a little extra matter onto the Sun, the inward force of gravity would increase.

## What is an example of hydrostatic pressure?

Blood is a fluid, so blood has a hydrostatic pressure. Increased elevation increases the amount of hydrostatic pressure. For example, the veins and capillaries in our feet have about 100 mm Hg more pressure inside than those at heart level.

## What are the common forms of the hydrostatic equation?

The way we determine this is through an equation: P = rho * g * d, where P is the pressure, rho is the density of the liquid, g is gravity and d is the depth. You may also see the hydrostatic equation written as P = rho * g * h, where the h stands for height.

## What is hydrostatic principle?

The principle of hydrostatic equilibrium is that the pressure at any point in a fluid at rest (whence any point in a fluid at rest (whence, “hydrostatic”) is just due to the weight of the overlying fluid.

## What happens to a star if it is no longer in hydrostatic equilibrium?

When that happens, the star can no longer hold up against gravity. Its inner layers start to collapse, which squishes the core, increasing the pressure and temperature in the core of the star.

## What are the two forces involved in hydrostatic equilibrium?

Hydrostatic equilibrium says that there is a balance between two forces at every point within a star. One force is the inward force of gravity. The other force is the pressure in the gas caused by its temperature (recall that the pressure in an ideal gas is proportional to its temperature).

## Is the moon in hydrostatic equilibrium?

The smallest body confirmed to be in hydrostatic equilibrium is the dwarf planet Ceres, which is icy, at 945 km, whereas the largest body known to not be in hydrostatic equilibrium is the Moon, which is rocky, at 3,474 km.

## What is hydrostatic balance in atmosphere?

If the net upward pressure force on the slab is equal to the downward force of gravity on the slab, the atmosphere is said to be in hydrostatic balance.

## When was the hydrostatic balance invented?

1586

## What star balances the most gravity?

In any given layer of a star, there is a balance between the thermal pressure (outward) and the weight of the material above pressing downward (inward). This balance is called hydrostatic equilibrium.

## Which layer of sun is its surface?

Photosphere