Pressure in Fluids & Atmospheric Pressure [Physics only]

Pressure at a surface

• A fluid is a liquid or a gas. Pressure in a fluid causes a force normal (at right angles) to any surface (recall this equation):

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

• $p$ pressure in pascals, Pa; $F$ force normal to the surface in N; $A$ area of the surface in m². 1 Pa $=$ 1 N/m²
• Worked example: a 600 N person standing on two feet of total area 0.05 m² exerts $p = \dfrac{600}{0.05} = 12\,000$ Pa