\documentclass[tikz,border=6mm]{standalone}
\usepackage{tikzphysics}

\begin{document}
\begin{tikzpicture}[>=stealth]
  \node[curved-ramp, curved ramp floor length=2.5cm,
        curved ramp radius=4cm, curved ramp angle=90,
        curved ramp back extension=1cm] (R) at (0,0) {};

  % The curve guide anchors are symmetric about R.curve-60. A node placed
  % midway on this short guide line is therefore both positioned on the
  % circular surface and rotated to its exact local tangent.
  \path (R.curve-tangent-before-60) -- (R.curve-tangent-after-60)
    node[midway,sloped,block,minimum width=1cm,
         minimum height=0.75cm,anchor=south] (B) {$m$};

  \draw[->,blue,thick] (R.curve-60) -- (R.curve-normal-60)
    node[above] {$N$};
  \draw[dashed] (R.curve-center) -- (R.curve-60)
    node[midway,left] {$r$};
  \fill (R.floor-mid) circle (1.2pt) node[above] {\texttt{floor-mid}};
  \fill (R.curve-20) circle (1.2pt) node[above left] {\texttt{curve-20}};
  \fill (R.curve-80) circle (1.2pt) node[above right] {\texttt{curve-80}};
\end{tikzpicture}
\end{document}
