Properties of Fluids — Formula Sheet

P = F/A (Pressure = Thrust / Area)

P = ρgh (Hydrostatic pressure at depth h)

P₁ - P₂ = ρgh

P_atm = hρg = 0.76 × 13600 × 9.8 ≈ 1.01 × 10⁵ Pa

Buoyant Force B = Weight of fluid displaced = ρ_fluid × V_submerged × g

Condition for floating: Weight of object = Buoyant force → ρ_object × V_total × g = ρ_fluid × V_submerged × g

F₂ = F₁ × (A₂/A₁)

P = F₁/A₁ = F₂/A₂ (Pressure is same throughout enclosed fluid)

T = F/L (Surface Tension = Force per unit length)

T = W/A (Surface Tension = Work done / Increase in surface area)

Excess pressure inside Liquid Drop: P = 2T/r

Excess pressure inside Soap Bubble: P = 4T/r

Pressure is defined as force (thrust) per unit area

P = F/A. SI unit is Pascal (Pa) = N m⁻².

Pressure at depth h below free surface

P = P_atm + ρgh. The term ρgh is the gauge pressure.

Hydrostatic pressure at depth h

P = Pₐₜₘ + ρgh

Mechanical advantage = A₂/A₁ (ratio of piston areas)