500 N
\begin{tikzpicture}
\draw (0,0) -- (5,0);
\draw (0,0) -- (0,-0.2);
\draw (5,0) -- (5,-0.2);
\draw (0,0) node[left] {A};
\draw (5,0) node[right] {B};
\draw (2.5,0.5) -- (2.5,1);
\draw (2.5,1) node[above] {500 N};
\draw (0,-0.5) -- (3,-0.5);
\draw (3,-0.5) -- (3,-0.7);
\draw (3,-0.5) node[below] {3 m};
\draw (3,-0.5) -- (5,-0.5);
\draw (5,-0.5) -- (5,-0.7);
\draw (5,-0.5) node[below] {2 m};
\draw (5,0) -- (6,1);
\draw (6,1) -- (6.2,1.2);
\draw (6.2,1.2) -- (6.2,1);
\draw (6,1) -- (6.2,0.8);
\draw (6.2,0.8) -- (6,1);
\draw (5.5,0.5) node[above] {5};
\draw (5.8,0.2) node[right] {3};
\draw (5.5,0.2) node[right] {4};
\end{tikzpicture}
(a)
