Buoyancy Force Calculator Formula

Understand the math behind the buoyancy force calculator. Each variable explained with a worked example.

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Formulas Used

Buoyant Force

buoyancy = fluid_density * 9.81 * volume

Equivalent Mass Supported

buoyancy_kg = fluid_density * volume

Variables

VariableDescriptionDefault
fluid_densityFluid Density (rho)(kg/m^3)1000
volumeSubmerged Volume (V)(m^3)0.05

How It Works

Archimedes' Principle

Any body submerged in a fluid experiences an upward buoyant force equal to the weight of the displaced fluid.

Formula

F_b = rho_fluid x g x V_displaced

where rho_fluid is the fluid density, g = 9.81 m/s^2, and V_displaced is the volume of fluid pushed aside by the object. An object floats when the buoyant force equals its weight.

Worked Example

A 0.05 m^3 object fully submerged in water (1000 kg/m^3).

fluid_density = 1000volume = 0.05
  1. 01F_b = 1000 x 9.81 x 0.05 = 490.5 N
  2. 02Equivalent mass = 1000 x 0.05 = 50 kg
  3. 03If the object weighs less than 490.5 N, it will float.

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