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10TH GRADE · HYDROSTATICS

Density and strength of Archimedes

Density of matter, buoyant force and floating of bodies.

18 minutes9 theory cards
Open interactive lesson

LESSON MATERIAL

Basic Concepts

2

Archimedes' Law

A force acting upward on a submerged body is equal to the weight of the displaced liquid or gas.

Ejection occurs due to the difference in pressure from below and above and depends on the density of the medium and the volume of the immersed part.

Sailing condition

A body floating without acceleration is in equilibrium under the influence of gravity and the Archimedes force.

For a floating body, the Archimedes force is equal to the force of gravity. The fraction of the immersed volume is determined by the ratio of the densities of the body and the medium.

LESSON MATERIAL

Physical quantities

2

Density

ρ\rho

Mass of a substance per unit volume.

Unit: kilogram per cubic meter · kgm3\frac{\mathrm{kg}}{\mathrm{m}^3}

Archimedes' force

FAF_A

The buoyant force of a liquid or gas.

Unit: newton · N\mathrm{N}

LESSON MATERIAL

Lesson formulas

5

Archimedes' force

FA=ρgVF_A=\rho gV

The Archimedes force is equal to the weight of the displaced medium.

Body floating condition

FA=mgF_A=mg

When swimming without acceleration, Archimedes' force is equal to the force of gravity.

Mass through density and volume

m=ρVm=\rho V

Mass equals density times volume.

Determination of density

ρ=mV\rho=\frac{m}{V}

Density is equal to mass divided by volume.

Gram per cubic centimeter

1 gsm3=1000 kgm31\,\frac{\mathrm{g}}{\mathrm{sm}^3}=1000\,\frac{\mathrm{kg}}{\mathrm{m}^3}

One gram per cubic centimeter is equal to a thousand kilograms per cubic meter.

DIRECTORY

Related formulas

Densityρ · kg/m³