A seismometer of mass \(30 \mathrm{~g}\) and stiffness \(40 \mathrm{~N} / \mathrm{m}\) is used to measure the vibrations of a SDOF system of mass \(60 \mathrm{~g}\) and natural frequency \(150 \mathrm{rad} / \mathrm{s}\). It is feared that the mass of the seismometer may affect the vibrations that are to be measured. Check this out by calculating the natural frequencies of the two degree-of-freedom system with the seismometer attached.