$4-73.$ As air flows over the plate, frictional effects on its surface tend to form a boundary layer

in which the velocity profile changes from that of being uniform to one that is parabolic,

defined by $u=[1000y-83\mathrm{.}33({10}^3)y^2]\frac{m}{s},$ where $y$ is in meters, If the plate is

$0\mathrm{.}2$ m wide and this change in velocity occurs within the distance of $0\mathrm{.}5$ m $,$ determine the

mass flow through the sections $AB$ and $CD.$ Since these results will not be the same, how

do you account for the mass flow difference? Take $=1\mathrm{.}226k\frac{g}{m^3}.$