Final answer:
Wing tip vortices after a heavy plane has passed dissipate very slowly (option C). These vortices are created by the pressure difference over the wing and can be hazardous to other aircraft due to their stability and resistance to dissipation.
Step-by-step explanation:
Dissipate very slowly:
Wing tip vortices after an airplane has passed is C. dissipate very slowly. Wing tip vortices are spirals of air created by the difference in pressure between the top and bottom of an airplane wing. These vortices can be hazardous to other aircraft and do not dissipate immediately.
Wing tip vortices can persist because they consist of rapidly rotating air with a low-pressure center, which makes them stable and resistant to dissipation. They can spread out over time and are affected by several factors, including the speed and weight of the aircraft that created them, ambient atmospheric conditions, and the presence of any turbulence in the atmosphere.
Generally, heavier aircraft flying at higher speeds produce stronger vortices that take longer to dissipate. Due to the persistence of the vortices, pilots are advised to maintain a safe distance behind large aircraft to avoid potential turbulence and control difficulties. Air traffic control systems often implement minimum separation standards to ensure safety.