4.3 In the two-dimensional steady laminar boundary layer on a flat plate with constant free-stream velocity U.., the boundary-layer equations are given, assuming constant thermophysical prop- erties and negligible viscous dissipation, by + = 0, ax Ju + V = V ay' aT aT u +v = a where v is the kinematic viscosity and a the thermal diffusivity of the fluid. Let the free-stream and the plate be isothermal at constant temperatures T. and Tw, respectively. Show that, without solving these equations, if Pr = 1 then Nux = 1 2 Cf Rex, W where Nux, Cr, and Re, are the local Nusselt number, friction coefficient and Reynolds number, respectively.