Best exhibited by a basic pendulum, FTP, name this type of periodic motion often abbreviated as SHM.
For systems that execute it, a particle's displacement is defined as "amplitude times the cosine of angular frequency multiplied by time."  The French mathematician Jean-Baptiste-Joseph Fourier's discovery of its descriptive use is now used to explain such things as the movement of electrons in a wire carrying AC current.  It occurs in the case in which a particle or mass oscillates about an equilibrium point subject to a linear force.  Best exhibited by a basic pendulum, FTP, name this type of periodic motion often abbreviated as SHM.
For systems that execute it, a particle's displacement is defined as "amplitude times the cosine of angular frequency multiplied by time."  
simple harmonic motion