Pressure (WJEC GCSE Physics): Revision Note

Pressure

• Pressure is exerted when a force acts over an area

• Therefore, pressure can be calculated using:

  $\mathrm{pressure}=\frac{\mathrm{force}}{\mathrm{area}}$

  $p=\frac{F}{A}$

• Where:

  • p = pressure measured in pascals (Pa)

    • 1 pascal is equivalent to 1 newton per meter squared

    • 1 Pa = 1 N / m²

  • F = force measured in newtons (N)

  • A = area measured in metres squared (m²)

• The area should always be the cross-sectional area of the object

• So that the force is at a right angle to the surface it is acting upon

• Higher Tier students will need to be able to rearrange the pressure equation

Pressure, Force, Area Equation Triangle

Cover up the variable you need to calculate, and the triangle shows you how the equation is arranged

• Pressure can be exerted by a solid on another solid

  • For example the pressure exerted by a person standing on the ground

• Pressure can be exerted by a gas on a surface

  • For example when gas particles collide with the surfaces of a container

Gas Particles Colliding with the Walls of a Container

Gas particles collide with the surfaces of a container producing a force that acts over an area