Natural Or Resonant Frequency
WARNING: This page does not describe the selected car, but rather 58 other vehicles, including the 2003 Saturn Vue, 2003 Saturn L300, 2003 Saturn Ion 3, 2003 Saturn Ion 2, and 2003 Saturn Ion 1. However, it is still accessible from the selected car via links, so may be relevant.
The natural frequency is the frequency at which an object tends to vibrate. Bells, guitar strings, and tuning forks are all examples of objects that tend to vibrate at specific frequencies when excited by an external force.
Suspension systems, and even engines within the mounts, have a tendency to vibrate at certain frequencies. This is why some vibration complaints occur only at specific vehicle speeds or engine RPM.
The stiffness and the natural frequency of a material have a relationship. Generally, the stiffer the material, the higher the natural frequency. The opposite is also true. The softer a material, the lower the natural frequency. Conversely, the greater the mass, the lower the natural frequency.