I would complete to my pic adding the draw of two people that are pushing a crate, like this figure or similar. How can you help me?
Here's the code:
\documentclass{standalone}
\usepackage{bm}
\usepackage{tikz}
\usetikzlibrary{patterns,calc}
\begin{document}
\begin{tikzpicture}
\pattern[pattern=north east lines,thin] (0,0) rectangle (12,-.5 );
\draw (0,0) -- (12,0);
\draw[very thick] (3,0) rectangle +(6,3);
\draw[very thick,blue,->] ($(8,1.5)+(1,0)$) -- +(2,0) node[very near end,below] {$\vec{F}$};
\draw[very thick,red,->] ($(1,1.5)+(-.0,0)$)-- +(2,0) node[very near start,below] {$\vec{F}$};
\end{tikzpicture}
\end{document}


\includegraphicsas @Johannes_B suggests. – Torbjørn T. May 08 '16 at 09:02tikzsymbolsmay also be useful as it has stick figures with options for limb angles etc. – cfr May 08 '16 at 14:49