Basically, a passive radiator is a reactionary device as the name suggests. When a driver (such as a subwoofer) is mounted to a sealed speaker box (enclosure), the physical forward/back movement of the speaker affects the internal air pressure of the enclosure.
Three landforms created by wind are; sand dunes, yardangs (half-teardrop shaped formations hill sized, and deflation hollows (wind swept depressions.
Landforms are the natural shapes, or features on Earth. Landforms are shaped by earthquakes, volcanic activity, and the movement of tectonic plates. They are also shaped by processes like weathering and erosion.