A metal sphere of radius 1 mm and mass 50 mg falls vertically in glycerine. Find (a) the viscous force exerted by the glycerine on the sphere when the speed of the sphere is 1 cm s-1, (b) the hydrostatic force exerted by the glycerine on the sphere and (c) the terminal velocity with which the sphere will move down without acceleration. Density of glycerine `=1260kgm^-3` and its coefficient of viscosity at room temperature = 8.0 poise.

Options

A. `3xx10^(-4)N`
B. `1.5xx10^(-4)N`
C. `4.5xx10^(-4)N`
D. `0.5xx10^(-4)N`

Answer

B

Explanation

Viscour force `=6pietarv`