A grain of pollen is falling at terminal velocity. The fluid is air. Calculate the coefficient of

Question:

A grain of pollen is falling at terminal velocity. The fluid is air. Calculate the coefficient of drag. Idealize the pollen grain as a smooth sphere with a diameter of 50 microns. The terminal velocity is 6.0 cm/s. The air has a kinematic viscosity of 15.0 × 10⁶ m²/s. Choose the closest answer:

(a) 0.8, or less,

(b) 1.8,

(d) 88, or

(e) 120 or greater.