# Forces: Fluid Pressure

## Fluid Pressure

### Basics of Fluid Pressure

• Fluid Pressure can be explained as the force per unit area applied by a fluid when it’s in a state of rest.

• Fluids include both liquids and gases, and both increase pressure with depth.

• Fluid pressure can be found in all directions, not just down. This is why you can feel water pressure on all sides when you dive into a pool.

### Calculation of Fluid Pressure

• The formula to find fluid pressure is pressure = height of column x density of liquid x gravity.

• Remember the unit for pressure is Pascal (Pa), the unit for density is kilograms per cubic metre (kg/m³), and gravity is approximately 9.8 m/s².

• Using this formula you can calculate the pressure at any depth in a stationary fluid.

### The Impact of Atmospheric Pressure

• Atmospheric pressure, also known as air pressure, is the pressure within the atmosphere of Earth.

• Air pressure decreases as altitude increases.

• The lower pressure at higher altitudes can impact physical abilities, e.g. athletes may struggle to breathe and perform at their peak.

• Common instruments for measuring air pressure include barometers and manometers.

### Pascal’s Principle

• Pascal’s Principle states that the pressure applied at any point in a fluid in a confined space is transmitted equally in all directions.

• This principle is essential in hydraulic systems where a small force applied to a small area can generate a large force over a larger area.

• This principle is used in several real-life applications like hydraulic lifts in car garages, hydraulic brakes in vehicles, and even in various heavy machinery machinery.