Archimedes’ principle

Definition

Archimedes’ principle states that a body immersed in a fluid experiences a buoyant force equal to the weight of the fluid displaced by the body. This principle explains why objects float or sink.

5 Must Know Facts For Your Next Test

1. The buoyant force acts upwards, opposing the weight of the object.
2. An object will float if its density is less than the density of the fluid it displaces.
3. The principle applies to both liquids and gases.
4. Archimedes’ principle can be used to determine an object's volume and density via fluid displacement methods.
5. The magnitude of the buoyant force can be calculated using $F_b = \rho_f V_f g$, where $\rho_f$ is the fluid density, $V_f$ is the volume of displaced fluid, and $g$ is gravitational acceleration.

Review Questions

• What does Archimedes' principle state about an object immersed in a fluid?
• How do you calculate the buoyant force acting on an object submerged in water?
• Under what condition will an object float when placed in a fluid?

Related terms

Buoyant Force:

The upward force exerted by a fluid that opposes the weight of an immersed object.

Density:

A measure of mass per unit volume; it determines whether an object will float or sink in a given fluid.

Fluid Displacement:

The process by which an object submerged in a fluid pushes aside or displaces a certain amount of that fluid.