Archimedes’ Principle state that “ When an object is immersed in a fluid (a liquid or a gas) ,the buoyant force
( upthrust force) on the object is equal to the weight of fluid displaced by the object.
From Archimedes’s Principle :
Buoyant Force, Fb = Weight of fluid displace
= mg (note : F = ma)
= ρVg (note : ρ = m/V )
Thus Fb = ρ V g
Where Fb = Bouyant Force or Upthrust
ρ = Density of fluid
V = Volume of fluid displaced or the volume of the object that immersed in the fluid.
Equation for buoyant force
1. Buoyant force = Weight of fluid displaced
2. Buoyant force = ρVg
3. Buoyant force = Weight object in air – weight in water