After installation, it was found that a particular machine exhibited excessive vibration due to a harmonic excitation force with a frequency of \(100 \mathrm{~Hz}\). A dynamic absorber was designed and added to the original system to attenuate this vibration. If the resulting vibration magnitude of the absorber mass was \(2 \mathrm{~mm}\) at \(100 \mathrm{~Hz}\) and the excitation force magnitude was \(25 \mathrm{~N}\), determine the stiffness of the spring \((\mathrm{N} / \mathrm{m})\) and mass \((\mathrm{kg})\) used to construct the absorber. You may neglect damping in your analysis.