Calculate the velocity a spherical raindrop would achieve falling (take downward as positive) from 4.2 km in the following situations.

(a) calculate the velocity in the absence of air drag.

(b) calculate the velocity with air drag. take the size across of the drop to be 4.8 mm, the density of air to be 1.17 kg/m3, the density of water to be 1000 kg/m3, the surface area to be πr2, and the drag coefficient to be 1.0.