Fluid Statics — A/L Physics

What must I remember about Fluid Statics?

• Density and Relative Density: Density ρ = m / V; Relative Density (Specific Gravity) = Density of substance / Density of pure water at 4 °C.
• Pressure in Fluids: Pressure P = dF / dA; Hydrostatic pressure at depth h in liquid: P = P_atm + h ρ g; Gauge Pressure P_gauge = h ρ g.
• Pascal's Principle: Pressure applied to an enclosed incompressible fluid is transmitted undiminished to every portion of the fluid and the walls of the vessel (Hydraulic Press: F1/A1 = F2/A2).
• Archimedes' Principle & Law of Flotation: Archimedes: When a body is wholly or partially immersed in a fluid, it experiences an upward buoyant force (Upthrust U) equal to the weight of fluid displaced: U = V_immersed * ρ_fluid * g; Law of Flotation: A floating body displaces a weight of fluid equal to its own total weight.

Test yourself (1 minute)

1. Atmospheric Pressure measurements

   Standard atmospheric pressure = 1 atm = 760 mmHg = 1.013 × 10⁵ Pa; Fortin's Barometer uses mercury because of its high density (compact column height) and very low vapor pressure.

2. Apparent weight of immersed body

   W_apparent = W_true - Upthrust = V ρ_body g - V ρ_fluid g = V g (ρ_body - ρ_fluid).

3. Manometer differential equation

   P_gas = P_atm ± h ρ g depending on liquid level difference.

Practise Fluid Statics questions today

Source: NIE G.C.E. (A/L) Physics Resource Book - Unit 2: Mechanics & Fluid Statics

What should I study first?

What comes next?

Next in the syllabus

Where does Fluid Statics fit in the syllabus?

Unit 2.6 · Year 1 · Term 1