What is the term for vibration at the natural frequency?

• A. Damping
• B. Harmonics
• C. Natural frequency of vibration
• D. Resonance

Answer: (C)

The vibration at the natural frequency is described by the natural frequency of vibration. This is the inherent rate at which a system tends to oscillate if displaced and then left free to vibrate, determined by the system’s mass and stiffness (and damping). It represents the specific frequency the system prefers to vibrate at when not externally forced.

Damping is about energy loss in the system, not the frequency itself. Harmonics are higher-frequency components that are integer multiples of a fundamental frequency, not the fundamental natural frequency itself. Resonance is the phenomenon of a large-amplitude response when a system is driven at its natural frequency; it describes the effect, not the frequency label.