Determine the output from the seismometer of Chapter Problem 6.15 if the \(60 \mathrm{~g}\) mass is given an initial velocity of \(15 \mathrm{~m} / \mathrm{s}\). Use a two degree-of-freedom system, remembering that the seismometer records the relative displacement between the seismic mass and the body whose vibrations are to be measured.

Data From Chapter Problem 6.15:
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.