Final answer:
A rectangular wing is mounted in a low-speed subsonic wind tunnel to study wing performance and aerodynamic forces at low speeds.
Step-by-step explanation:
In a low-speed subsonic wind tunnel, a rectangular wing is mounted to study wing performance in such conditions. This setup allows researchers to observe and analyze the aerodynamic forces, lift, and drag on the wing. It helps in understanding the behavior and characteristics of the wing design at low speeds before testing it in actual flight conditions.