Lifting Bag - Physics of Buoyant Lifting

Physics of Buoyant Lifting

See also: Buoyancy and Archimedes' principle

The volume of the bag determines its lifting capacity: a 100-litre (4 cu ft) bag can lift a 100-kilogram (220 lb) underwater object.

A partially filled bag will accelerate as it ascends because the air in the bag expands as the pressure reduces on the ascent, following Boyles law, increasing the bag's buoyancy, whereas a full bag will overflow or blow off excess volume and maintain the same volume and buoyancy providing is does not descend. A bag which leaks sufficiently to start sinking will lose volume to compression and become less buoyant in a positive feedback loop until stopped by the bottom.

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