Question

What is the point of harmonically exciting a dynamics system

Answer 1

Many dynamical systems in the physical world are harmonically excited such that we design the dynamics system in such a way that the resonance condition is eliminated. If the excitation frequency matches with the natural frequency of the system a condition called as resonance occurs which keeps on increasing the amplitude of the system within permissible limit ( If system is damped) or the amplitude goes to infinity ( if system is undamped).

This is the reason we check for the responses and amplitude of the system after harmonically exciting the system.