A body of density `D_(1)` and mass M is moving downward in glycerine of density `D_(2)` . What is the viscous force acting on it?

Options

A. `Mg(1-(D_(2))/(D_(1)))`
B. `Mg(1-(D_(1))/(D_(2)))`
C. `MgD_(1)`
D. `MgD_(2)`

Answer

A

Explanation

Volume of the body = `(M)/(D_(1))`
Mass of liquid displaced by body `M=((M)/(D_(1)))D_(2)`
Viscous force= Effective weight of the body
`:. F=Mg-Mg=(M-M.)g` `=(M-(MD_(2))/(D_(1)))g=Mg(1-(D_(2))/(D_(1)))`