The top acceleration response $(g)$ of the model under the earthquake during the experiment conducted on Friday's lecture has been uploaded in a file named top$\_$response.txt on Moodle. Using this response, calculate the first natural frequency of the model by taking FFT$.$ The data was recorded at $200Hz.$ You can send the time history graph and the FFT result as the homework solution. $($Hint: First modal frequency: $4\mathrm{.}54Hz.)$