A small metal sphere of radius 'r' and density 'ρ' falls from rest in a viscous liquid of density 'σ' and coefficient of viscosity 'η'. Which expression represents the time 't' it takes for the sphere to attain one-half of its terminal velocity (neglecting buoyancy)?
(2ρr²ln2)/(9η)
(4ρr²ln2)/(9η)
(ρr²ln2)/(9η)
(2ρr²ln3)/(9η)
Related Questions
Consider a rain drop falling through air with a terminal velocity 'v'. If the air pressure suddenly decreases but the temperature remains constant, how will the terminal velocity be affected?
Increases
Decreases
Remains the same
Cannot be determined
