[Tex/LaTex] How to produce the symbols representing sign conventions for forces and moments in mechanical equilibrium equations

Question

Engineering texts often use a straight or curved arrow paired with a "plus" sign to indicate the sign convention for forces and moments at the beginning of an equilibrium equation. For example, see the below image from an engineering textbook, where I have circled in red three of these symbols:

My experience has been that these symbols are standard and common but I can't find a way to create them using any TeX/LaTeX markup or library. Do I have to somehow create them from scratch? Most of my familiarity with TeX and LaTeX comes from using MathJax here on Stack Exchange.

Answer 1

You can combine existing symbols.

\documentclass{article}
\usepackage{amsmath,amssymb}
\usepackage{graphicx}

\makeatletter

\newcommand*\curveplus{%
  \mathbin{\rotatebox[origin=c]{90}{$\m@th\curvearrowleft$}+}}

\newcommand*\rightplus{%
  \mathpalette\@rightplus\relax}
\newcommand*\@rightplus[1]{%
  \mathbin{\vcenter{\hbox{$\m@th\overset{#1+}{\to}$}}}}

\newcommand*\upplus{%
  \mathbin{+\mathord\uparrow}}

\makeatother

\begin{document}


$\curveplus \sum M_A = 0$

$\rightplus \sum F_x = 0$

$\upplus \sum F_y = 0$

\end{document}