\begin{tikzpicture}
%Place the nodes
\node[terminal={below}{$f(t)$}] (a) at (0,0) {};
\node[terminal={below left}{$y_1$}] (b) at (3cm,0) {};
\node[terminal={below left}{$\ddot{y}_2$}] (c) at (6cm,0) {};
\node[terminal={[xshift=-4mm]below right}{$\dot{y}_2=x_2$}] (d) at (9cm,0) {};
\node[terminal={below right}{$y_2=x_1$}] (e) at (12cm,0) {};
%Draw the connections
\draw[amark=$1/K$] (a) to (b);
\draw[amark=$K/M$] (b) to (c);
\draw[amark=$s^{-1}$] (c) to (d);
\draw[amark=$s^{-1}$] (d) to (e);
\draw[amark=$-B/M$] (d) to[bend left=45] (c);
\draw[amark=$1$,label revd] (e) to[bend left=50] (b);
\draw[amark=$-K/M$,label revd] (e) to[bend right=50] (c);
\end{tikzpicture}