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 From Wave Erosion. 1  Wave-cut cliffs form when waves erode a rocky shoreline. They create a vertical wall of exposed rock layers. 2  Sea arches form when waves erode both sides of a cliff. They create a hole in the cliff. 3  Sea stacks form when waves erode the top of a sea arch. This leaves behind pillars of rock.