The weight of the displaced medium  = ........................(6) 
where is the density of the liquid.

The net downwards force acting on the body is,
                                         .....................(7)
At equilibrium, i.e., when the two body moves with terminal velocity, eqn(1) and (7) can be equated as follows,
                     
            or                   ................................(8)

              The floating of clouds and falling of rain drops can be explained based on the above equation. The cloud consists of tiny water drops of radius as small as cm. The viscosity of atmospheric air is about poise. From eqn(8) the terminal velocity of above droplets are found to be around 1.2 cm/sec. Because of such low the tiny water droplets float as clouds.

             When the above water drops coalesce into bigger drops of radius about cm, they attain a terminal velocity of about 190 m/s and then fall through the air as rain drops.