What does 'resonance' mean in mechanical systems?

Resonance in mechanical systems refers to a condition where a system vibrates at its natural frequency due to external forces. When an external force is applied at the same frequency as the natural frequency of the system, the amplitude of the vibrations can increase significantly. This phenomenon occurs because the system effectively absorbs energy from the external force, leading to potentially large oscillations. Understanding resonance is crucial in engineering, as it can lead to destructive outcomes if not properly managed, such as in the case of bridges and buildings that can suffer structural failure from resonance with wind or seismic activities. Overall, resonance is a key concept in the analysis and design of mechanical systems, as it dictates how systems respond to periodic forces.