In gliding (unpowered) flight, lift and drag are in equilibrium with the weight. Show, that with no wind, the craft sinks at an angle tanθ ≈ drag/lift. For a sailplane with m = 200 kg, wing area = 12 m2, AR = 12, with an NACA 0009 airfoil, estimate (a) stall speed, (b) minimum gliding angle; (c) the maximum distance it can glide in still air at z = 1200 m.