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 created by erosion. The coastline is constantly eroding. There are four key types of erosion: Abrasion-Waves transport material which hit the cliff and gradually wear it away. Hydraulic action-As waves approach the coast they trap air and force it into gaps in the cliff.Eventually this weakens the rock.tages in cliff retreat: Waves attack the bottom of the cliff, particularly during storms and at high tide. Eventually a wave-cut notch [wave cut notch: An area of erosion at the base of a cliff formed by the waves.] is formed. At the same time weathering attacks and weakens the top of the cliff.