Question

Spherical balls of radius $'R'$ are falling in a viscous fluid of viscosity '$\eta$' with a 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

Retarding viscous force $= 6p?Rv$