Question

Spherical balls of radius R are falling in a viscous fluid of velocity v The retarding viscous force acting on the spherical ball is

• A. Directly proportional to R but inversely proportional to v.
• B. Directly proportional to both radius R and velocity v.
• C. Inversely proportional to both radius R and Velocity v
• D. Inversely proportional to R but directly proportional to velocity v

Answer 1

Answer: (B)

Directly proportional to both radius R and velocity v.

Answer 2

According to stokes’ law

Viscous drag force, $F = 6\pi\eta Rv$