For a particle falling through water at its terminal settling velocity, which of the following holds true?
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Answer: B. Weight = buoyancy + drag
Explanation
Terminal settling velocity represents a steady state where all vertical forces cancel out. Gravity pulls the particle downward with a force equal to its total mass weight. Upward buoyant force and hydrodynamic drag combine to precisely counteract the gravitational weight. Terminal velocity is reached when net acceleration of a falling particle becomes zero. Buoyancy acts upward according to Archimedes principle based on displaced fluid volume. Drag force depends on fluid viscosity, particle velocity, and projected cross-sectional area.
Particle settling principles are essential for designing industrial sedimentation tanks and clarifiers. Chemical processing industries utilize terminal velocity calculations for designing slurry transport pipelines. Geological sedimentation studies rely on settling velocity to analyze suspended particle sizes. Stating buoyancy equals weight plus drag incorrectly ignores the downward direction of gravity. Stating drag equals buoyancy plus weight incorrectly places drag on the wrong equation side. Ignoring buoyancy would incorrectly imply only drag resists gravity in submerged fluid environments.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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