Archimedes’ principle

Definition

Archimedes' principle states that the buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. This principle explains why objects float or sink depending on their density relative to the fluid.

5 Must Know Facts For Your Next Test

1. The buoyant force can be calculated using the formula $F_b = \rho_f V g$, where $\rho_f$ is the fluid density, $V$ is the volume of displaced fluid, and $g$ is the acceleration due to gravity.
2. An object will float if its average density is less than that of the fluid it is submerged in.
3. The apparent weight of an object in a fluid is reduced by the magnitude of the buoyant force acting on it.
4. Archimedes' principle applies to both liquids and gases as fluids.
5. The principle was discovered by Archimedes when he noticed water displacement while taking a bath.

Review Questions

• What does Archimedes' principle state about buoyant force?
• How can you determine whether an object will float or sink using Archimedes' principle?
• What factors influence the buoyant force acting on a submerged object?

Related terms

Buoyancy:

The ability or tendency of an object to float in a fluid due to the upward buoyant force exerted by the displaced fluid.

Density:

A measure of mass per unit volume, typically expressed in kilograms per cubic meter (kg/m^3).

Hydrostatic Pressure:

$P = \rho gh$, where $P$ is pressure, $\rho$ is fluid density, $g$ is acceleration due to gravity, and $h$ is height/depth within the fluid.