Buoyant force

Definition

Buoyant force is the upward force exerted by a fluid on an object placed in it. It is equal to the weight of the fluid displaced by the object.

5 Must Know Facts For Your Next Test

1. Buoyant force is governed by Archimedes' Principle.
2. The magnitude of the buoyant force is equal to the weight of the displaced fluid.
3. An object will float if its density is less than that of the fluid, and sink if its density is greater.
4. Buoyant force acts through the center of buoyancy, which is the centroid of the displaced volume of fluid.
5. Objects experience buoyant force in both liquids and gases.

Review Questions

• What principle explains the concept of buoyant force?
• How can you determine whether an object will float or sink in a fluid?
• Where does buoyant force act through on an object submerged in a fluid?

Related terms

Archimedes' Principle:

States that any body completely or partially submerged in a fluid at rest is acted upon by an upward, or buoyant, force.

Density:

Mass per unit volume of a substance, often denoted as $\rho$.

Center of Buoyancy: The point through which the buoyant force acts on a submerged or floating object.