The ratio of the terminal velocities of two drops of radii R and `R//2` is

The ratio of the terminal velocities of two water drops while falling towards the earth's surface is 4:9 . Determine the ratio of the radii.

The terminal velocity of a liquid drop of radius 'r falling through air is v. If two such drops are combined to form a bigger drop, the terminal velocity with which the bigger drop falls through air is (ignore any buoyant force due to air)

A sphere of radius R and density rho_1 is dropped in a liquid of density sigma . Its terminal velocity is v_1 . If another sphere of radius R and density rho_2 is dropped in the same liquid, its terminal velocity will be:

The ratio of the volumes of two sphere is 8:27. If r and R are the radii of spheres respectively, then (R-r):r is___.