Fluid Pressure

Fluid Pressure

• Fluid = A liquid or gas, a substance that can 'flow' due to their particle's ability to move.
• Moving particles collide with surfaces and each other.
• Particles are light, but still have a mass and exert a force on the object they collide with, meaning particles exert a pressure.
• The pressure of a fluid means a force is exerted normal (at right angles) to any surface in contact with the fluid.
• Pressure in pascals (Pa) = Force normal to a surface (N) / Area of that surface (m squared)
• P = F/A
• Density - The measure/degree of compactness of a substance, meaning how close together the particles within a substance are.
• For a given liquid, the density is uniform (constant/the same through out); the density doesn't vary with shape or size.
• The more dense a given liquid is the more particles it has in a certain space, meaning there are more collisions taking place and therefore a higher pressure.
• As the depth of a liquid increases, so does the no. of particles above that point, adding weight to the pressure felt at that point meaning liquid pressure increases with depth.
• Pressure (Pa) = Height of the column of liquid in depth (m) x Density of the liquid (Kg/m cubed) x Gravitational field strength (N/Kg)
• P = hpg