Buoyant force or upthrust is the upward force exerted by a fluid that opposes the weight of an object immersed in a fluid.

The magnitude of the buoyant force determines whether an object will sink, float, or rise when submerged in a fluid.

**Formula to calculate buoyant force.**

- ρ is the fluid density.
- g is the acceleration due to gravity.
- V is the fluid volume.

**Example:**

Suppose the fluid density is 1Kg/m³, calculate the buoyant force if the volume of the fluid is 5 m³ and the acceleration due to gravity is 9.81 m/s².

Therefore, the buoyant force is -49.05 N.