Impulse Response is the response of a control system when the input is a unit impulse signal, represented by $r(t)=\delta(t)$ in the time domain and $R(s)=1$ in the Laplace domain. It is an important way to study the transient behavior, stability, natural dynamics, and speed of response of a system. For a system with transfer function $G(s)=Y(s)/R(s)$, the impulse response is $y(t)=\mathcal{L}^{-1}\{G(s)\}$, meaning that the inverse Laplace transform of the transfer function directly gives the system’s impulse response under zero initial conditions.