A steel storage tank is filled with gasoline. The tank has partially corroded on its inside, and small particles of rust have contaminated the fuel. The rust particles are approximately spherical, and they have a mean diameter of 25 µm and density of 5.3 g/cm³.

(a) What is the terminal velocity of the particles as they fall through the gasoline?

(b) How long would it take the particles to fall 5 m and settle out of the liquid?