Resonance

At resonance, there is maximum transfer of energy between the hand and the mass-spring system. Plotting amplitude $A$ with respect to $f_h$, shows a curve that is almost symmetrical about its peak $A_{max}$, i.e., it has a bandwidth measured a distance down from $A_{max}$.

Figure 9: A Resonator shows peak amplitude when the driving force is equal to the system's natural frequency.

Both the peak $A_{max}$ the bandwidth $\Delta f$ depend on the damping in the system:

1. heavily damped: $\Delta f$ is large and $A_{max}$ is small.
2. little damping: $\Delta f$ is small and $A_{max}$ is large, creating a sharp resonance.