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.
The 3 landforms created by wave erosion sometimes called coastal  erosion are headlands and bays, cliffs and wave cut platforms and  finally caves, arches, stacks and stumps â¦ . Wave erosion is the  wearing away of land and the removal of beach by wave currents.
Landforms created by erosion. The coastline is constantly eroding. There are four key types of erosion: 1  Abrasion-waves transport material which hit the cliff and gradually wear it away. 2  Hydraulic action-as waves approach the coast they trap air and force it into gaps in the cliff. 3  Eventually this weakens the rock.