What is the terminal speed?

Question

A rain drop of mass 0.034 gram with a radius of 0.2 cm attains a terminal speed when the drag force is equal to its weight (W=mg). Give air density 1.21 kg/m^3, effective surface area of the drop can be treated as

A= π*r^2. Drag coefficient C=1.

Calculate the terminal speed.

Answer 1

Drag force = .5(rho)(area)(vel)²C_d ... rho, area, mass and C_d are given. Drag force = mg. Yields 6.69 m/s