A boundary layer is a row where the velocity changes very rapidly in a narrow region near a solid body $($much more on this to come$).$ Suppose the boundary layer velocity profile below is given by

$u(y)=$Usin$(\frac{y}{2}),0y$

where $U$ is the velocity far from the wall. Consider air at $25$ and $101$ kPa $,$ calculate the stress stress for a $U=100\frac{m}{s},=3cm$ thickness boundary layer $($a$)$ at the solid boundary $).($b$)$ at the end of the boundary layer