A rectangular airfoil of \(9 \mathrm{~m}\) span and \(1.8 \mathrm{~m}\) chord moves horizontally at an angle of attack through still air at \(240 \mathrm{~km} / \mathrm{h}\). Calculate the lift and drag, and the power necessary to drive the airfoil at this speed through air of

(a) \(101.3 \mathrm{kPa}\) and \(15^{\circ} \mathrm{C}\), and

(b) \(79.3 \mathrm{kPa}\) and \(-18^{\circ} \mathrm{C} . C_{D}=0.035 ; C_{L}=0.46\). Calculate the speed and power required for condition (b) to obtain the lift of condition (a).