Pressure in a Liquid | Physics for GCSE/IGCSE - Year 11 PDF Download

Pressure in Liquids

• A fluid can be classified as either a liquid or a gas.

When an object is submerged in a fluid, the fluid applies pressure, compressing the object.

• This pressure is uniformly distributed across the entire fluid surface and extends in all directions.
• The pressure exerted on objects within fluids generates forces against surfaces.
• These forces operate perpendicular to the surface, at a 90-degree angle.

• The pressure exerted by a fluid on an object escalates with:
  • Greater depth within the fluid.
  • Enhanced density of the fluid.

Calculating Pressure in Liquids

• When determining the pressure in liquids, it is crucial to consider the difference in pressure at various depths within the liquid.
• This pressure can be calculated using the formula:
  Δp = ρgΔh
• Where:
  • Δp represents the change in pressure in pascals (Pa), where 1 Pa equals 1 N/m².
  • ρ stands for the density of the liquid in kilograms per cubic meter (kg/m³).
  • g denotes the gravitational field strength on Earth in newtons per kilogram (N/kg).
  • Δh indicates the change in height of the liquid column in meters (m).
• The pressure force on objects in a liquid is uniformly spread over the entire surface.