D. An airplane flies at a speed of 250 kilometers per hour (kph) at an altitude of 3000 m. Assume the transition from laminar to turbulent boundary layers occurs at critical Reynolds Number, RE cr, = 5 x 105 and that the boundary layers on the wing surface behave as a flat plate. At 3000 m: density air = 0.9093 kg/m; =1.694x105 (N-s/m) At sea level: density air = 1.225 kg/m; u=1.789x105 (N-s/m) 8. (10 pts) At 3000 m how far from the front edge (meters) does the laminar boundary layer extend. 9. (05 pts) If the plane descends to land at the sea-level maintaining 250 kph will the portion of the wing covered by the boundary layer increase or decrease, explain.