1 To comply with Department of Defense changes to common access cards, and to comply with Homeland Security Presidential Directive 12, the Fort Knox One Stop In-processing Center has recently started implementing changes to the CAC issuing process.
acoustics - the study of the physical properties of sound. acoustic radiation pressure - (acoustics) the pressure exerted on a surface normal to the direction of propagation of a sound wave. physical science, physics - the physical properties, phenomena, and laws of something; he studied the physics of radiation. harmonics - the study of musical sound.
Beat (acoustics) - Mathematics and physics of beat tones. 1  This phenomenon is best known in acoustics or music, though it can be found in any linear system: According to the law of superposition, two tones sounding simultaneously are superimposed in a very simple way: one adds their amplitudes.