A smooth flat plate with a sharp leading edge is placed along a gas stream flowing at U = 10 m/s. The thickness of the boundary layer at section r − s is 10 mm, the breadth of the plate is 1 m (into the paper) and the density of the gas $\rho$= 1.0 kg/m. Assume that the boundary layer is thin, two-dimensional, and follows a linear velocity distribution, u = U (y/$\delta$) , at the section r − s , where y is the height from plate.

The mass flow rate (in kg/s) across the section q − r is