A \(550-\mathrm{kg}\) industrial sewing machine has a rotating unbalance of \(0.24 \mathrm{~kg} \cdot \mathrm{m}\). The machine operates at speeds between 2000 and \(3000 \mathrm{rpm}\). The machine is placed on an isolator pad of stiffness \(5 \times 10^{6} \mathrm{~N} / \mathrm{m}\) and damping ratio 0.12 . What is the maximum natural frequency of an undamped seismometer that can be used to measure the steady-state vibrations at all operating speeds with an error less than 4 percent. If this seismometer is used, what is its output when the machine is operating at \(2500 \mathrm{rpm}\) ?