What is the velocity v of a metallic ball of radius r falling in a tank of liquid at the instant when its acceleration is one-half that of a freely falling body ? (The densities of metal and of liquid are r and s respectively, and the viscosity of the liquid is `eta`).

Options

A. `(r^2 g)/(9eta)(rho-2sigma)`
B. `(r^2 g)/(9eta)(2rho-sigma)`
C. `(r^2 g)/(9eta)(rho-sigma)`
D. `(2r^2 g)/(9eta)(rho-sigma)`

Answer

C

Explanation

Since,`v_T=2/9 r^2((g.)/(eta))(rho-sigma)=(r^2 g)/(9 eta)(rho-sigma). `(:. g.=g/2)`