an element for sensing shear stress is positioned in a flat plate 1 meter from the leading edge. the element simply consists of a small plate, 1 cm x 1 cm, mounted flush with the wall, and the shear force is measured on the plate. the fluid flowing by the plate is air with a free-stream velocity of 30 m/s, a density of 1.2 kg/m3, and a kinematic viscosity of 1.5 x 10-5 m2/s. the boundary layer is tripped at the leading edge. what is the magnitude of the shear stress acting on the element?