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.
If enough sediment is eroded away in one place, it can begin to form erosional landforms. A bay at place where a river meets the sea is an excellent example of an erosional landform. The size, shape, and scope of a bay can vary drastically by the composition of the rocks and soil surrounding it.