Fbuoyant​= ρfluid​⋅Vdisplaced​⋅g

Where:

  • Fbuoyant is the buoyant force,
  • ρfluid is the density of the fluid,
  • Vdisplaced is the volume of the fluid displaced by the immersed object,
  • g is the acceleration due to gravity.

The buoyant force is always directed upward, opposing the force of gravity acting on the object.

Real Life Examples

  1. Floating Objects:
    • Example: A ship floating on water
    • Explanation: The weight of the water displaced by the ship is equal to the buoyant force acting upward. As long as the weight of the ship is less than the buoyant force, it will float.
  2. Balloons in the Air:
    • Example: A helium-filled balloon rising in the air
    • Explanation: The buoyant force acting on the balloon is greater than its weight. This causes the balloon to rise, as helium is less dense than the surrounding air.
  3. Swimming:
    • Example: A person floating in a swimming pool
    • Explanation: When a person floats, the buoyant force acting on the person (due to the water displaced) equals their weight, allowing them to stay afloat.
  4. Hot Air Balloons:
    • Example: A hot air balloon ascending
    • Explanation: The heated air inside the balloon is less dense than the surrounding air, creating a buoyant force that exceeds the weight of the balloon and its contents.
  5. Ice Floating in Water:
    • Example: Icebergs in the ocean
    • Explanation: Because ice is less dense than water, a significant portion of an iceberg is submerged. The buoyant force acting on the iceberg keeps it afloat.

Further Reading