From mechanics, you may recall that when the acceleration of an object is proportional to its coordinate, d2xdt2=âkmx=âÏ2x, such motion is called simple harmonic motion, and the coordinate depends

From mechanics, you may recall that when the acceleration of an object is proportional to its coordinate, d2xdt2=âkmx=âÏ2x, such motion is called simple harmonic motion, and the coordinate depends on time as x(t)=acos(Ït+Ï), where Ï, the argument of the harmonic function at t=0, is called the phase constant.