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.
Coastal Landforms (Features of Erosion). Land forms on the coast are created or formed as a result of wave processes such as corrasion/abrasion, hydraulic, solution and attrition. These processes erode the coast and the material is transported and deposited along the coastline.