Calculate the speed (in m/s) a spherical rain drop would achieve falling from 2.80 km in the absence of air drag and with air drag. Take the size across of the drop to be 9 mm, the density to be 1.00 ✕ 10³ kg/m³, and the surface area to be r². (Assume the density of air is 1.21 kg/m³.)

in the absence of air drag