% projectile.tex — two coupled stocks (x- and y-position).
%
% A projectile launched at 30 m/s under angle 60 deg, landing back
% on the ground.  Demonstrates two parallel state evolutions plus a
% non-trivial \mstop expression.

\documentclass{article}
\usepackage[syntax=english]{numodel}

\begin{document}

\newmodelprefix{proj}

\mvar{T}{t}{0}{\s}{2}{systeem}
\mvar{Dt}{dt}{0.02}{\s}{2}{systeem}
\mvar{Vx}{v_x}{15}{\m\per\s}{3}{voorraad} 
\mvar{X}{x}{0}{\m}{3}{voorraad}
\mvar{G}{g}{-9.81}{\m\per\s\squared}{3}{constante}    % 30 cos 60 deg
\mvar{Vy}{v_y}{25.98}{\m\per\s}{3}{voorraad}  % 30 sin 60 deg
\mvar{Y}{y}{0}{\m}{3}{voorraad}

\mrule{Vy}{\projVy + \projG * \projDt}
\mrule{X}{\projX + \projVx * \projDt}
\mrule{Y}{\projY + \projVy * \projDt}
\mrule{T}{\projT + \projDt}
\mstop{\projY < 0}

\section*{Grafisch model}
\graphicmodel
  \directlua{
    local f = io.open("projectile.layout.txt","w")
    f:write(numodel.dump_layout("proj")); f:close()
  }

\section*{Simulatie}
\computemodel

\section*{Baan}
\diagrammodel{X}{Y}{proj-baan}

\end{document}