What is the buoyancy force acting in water on a fully submerged copper bar weighing 890 g?

Let’s translate all the values ​​from given to the SI system:
m = 890 g = 0.89 kg.
A buoyant force equal to the weight of the displaced fluid acts on a body immersed in a liquid, and is called the Archimedes force:
Fa = ρ * g * V, where ρ is the density of the liquid, g is the acceleration of gravity of a body raised above the Earth g = 9.8 m / s², V is the volume of the body.
We write down the formula for determining the mass, through the density:
m = ρ * V
Let us express them with this formula for the volume of the body:
V = m / ρ
According to the reference book, the density of copper is ρm = 8900 kg / m³, the density of water is ρw = 1000 kg / m³.
Let’s substitute all this in the formula for determining the buoyancy force:
Fa = ρw * g * V = ρw * g * m / ρm
Find the buoyant force:
Fa = ρw * g * m / ρm = 1000 * 9.8 * 0.89 / 8900 = 0.98 N
Answer: 0.98 N.