9. A wind-tunnel experiment is performed on a 1/25 scale model of a supersonic aircraft. The prototype aircraft flies at 450 m/s in conditions where the speed of sound is 250 m/s and the air density is 0.89kg/m³. The model aircraft is tested in a wind tunnel in which the speed of sound is 280m/s and the air density is0.56kg/m³. The drag force on the model is 100N. For dynamic similitude,determine the speed of flow in the wind tunnel, and the drag force on the prototype. (hint: Watch video “Chapter 7-Similitude.mp4")

Fig: 1