![A thin airfoil is mounted in a low-speed, subsonic wind tunnel, in which the Mach number is 0.1. At a point on the airfoil](https://www.gkseries.com/blog/wp-content/uploads/2023/09/A-thin-airfoil-is-mounted-in-a-low-speed-subsonic-wind-tunnel-in-which-the-Mach-number-is-0.1.-At-a-point-on-the-airfoil.jpg)
Q. A thin airfoil is mounted in a low-speed, subsonic wind tunnel, in which the Mach number is 0.1. At a point on the airfoil, the pressure coefficient is measured to be –1.2. If the flow velocity is increased such that the free-stream Mach number is 0.6, the pressure coefficient at the same point on the airfoil will approximately be:
(A) -3.5 (B) -2.9 (C) -1.5 (D) -0.75
Ans: -1.5