Buoyancy Force Calculator
Compare displaced-fluid force with object weight.
Apply Archimedes principle to displaced volume
Archimedes principle says buoyant force equals the weight of displaced fluid. This calculator multiplies fluid density, displaced volume, and gravitational acceleration, then compares that upward force with object weight from mass times gravity. The signed net result helps check whether a fully submerged object initially accelerates upward or downward under this simplified force balance.
With fluid density 1000 kilograms per cubic meter, displaced volume 0.02 cubic meter, object mass 15 kilograms, and gravity 9.81, buoyant force is 196.2 newtons. Weight is 147.15 newtons, leaving 49.05 newtons upward. A freely floating object would rise until its displaced volume decreases enough for buoyancy to equal weight.
Distinguish net force from final floating position
The model assumes a uniform fluid and uses the entered displaced volume, not automatically the object's total volume. It omits surface tension, drag, added mass, compressibility, fluid acceleration, and contact forces. Inputs remain in your browser. For partially submerged geometry, determine displacement from the submerged shape at the current orientation before trusting the force comparison.
Frequently Asked Questions
Is displaced volume always the full object volume?
Only when the object is fully submerged. A floating object displaces just enough fluid volume to balance its weight.
Why does gravity appear in both forces?
Gravity sets both displaced-fluid weight and object weight, so it cancels when comparing average densities.
Does positive net force guarantee stable floating?
No. Stability also depends on geometry, center of mass, center of buoyancy, and orientation.
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