\documentclass[12pt]{article}
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\begin{document}
\begin{equation*}
  \frac{dz}{dt} =
  \begin{bmatrix} z_4 \\ z_5 \\ z_6 \\
    -\frac{c}{m}\, z_4 \\
    -g - \frac{c}{m}\, z_5 \\
    0
  \end{bmatrix} + \begin{bmatrix} 0 \\ 0 \\ 0 \\ 
    \frac{1}{m} \cos\theta\, F_1 - \frac{1}{m} \sin\theta \, F_2 \\[1ex]
    \frac{1}{m} \sin\theta\, F_1 + \frac{1}{m} \cos\theta \, F_2 \\[1ex]
    \frac{r}{J}\, F_1
  \end{bmatrix}
\end{equation*}
\end{document}