During a cough, the velocity $v$ (in meters per second) of air in the trachea may be modeled by the function
$$v(r)=-120 r^{3}+80 r^{2}$$
where $r$ is the radius of the trachea (in centimeters) during the cough.
Estimate the radius of the trachea that produces the maximum velocity of air in the trachea. Use this radius to estimate the maximum velocity of air in the trachea.