Drawing a picture using Latex

Question

\begin{tikzpicture}
\tikz
\draw (0,0) circle [radius=1cm];
  \draw [thin, ->](-1,1) -- (0,1);
  \draw[thin, ->] (-1,1) -- (1,2);
  
\end{tikzpicture}

I can't make the second arrow inside the circle

Answer 1

Reproducing this chart is a bit more complicated but with the code you'll get the following figure:

Here's the full code:

\tikzset{every picture/.style={line width=0.75pt}}    
\begin{tikzpicture}[x=0.75pt,y=0.75pt,yscale=-1,xscale=1]
\draw   (123.32,140.84) .. controls (123.32,95.09) and (160.41,58) .. 
(206.16,58) .. controls (251.91,58) and (289,95.09) .. (289,140.84) .. 
controls (289,186.59) and (251.91,223.68) .. (206.16,223.68) .. controls 
(160.41,223.68) and (123.32,186.59) .. (123.32,140.84) -- cycle ;
\draw (289.5,29.34) -- (289.78,239.68) ;
\draw (215,32) -- (315,132) ;
\draw (206.16,140.84) -- (289,140.84) ;
\draw (265,82) -- (206.16,140.84) ;
\draw (236,141) -- (228.07,124.38) ;
\draw [shift={(226.78,121.68)}, rotate = 64.49] [fill={rgb, 255:red, 0; 
   green, 0; blue, 0 }  ][line width=0.08]  [draw opacity=0] 
 (8.93,-4.29) -- (0,0) -- (8.93,4.29) -- cycle    ;
\draw    (233.2,44.75) .. controls (255.43,27.74) and (277.96,28.93) .. 
(288.78,44.68) ;
\draw [shift={(230.78,46.68)}, rotate = 320.44] [fill={rgb, 255:red, 0; 
 green, 0; blue, 0 }  ][line width=0.08]  [draw opacity=0] (8.93,-4.29) 
 -- (0,0) -- (8.93,4.29) -- cycle    ;
\draw   (259.45,82) .. controls (259.45,78.93) and (261.93,76.45) .. 
 (265,76.45) .. controls (268.07,76.45) and (270.55,78.93) .. 
 (270.55,82) .. controls (270.55,85.07) and (268.07,87.55) .. 
 (265,87.55) .. controls (261.93,87.55) and (259.45,85.07) .. 
 (259.45,82) -- cycle ;
\draw   (283.45,140.84) .. controls (283.45,137.77) and (285.93,135.28) 
 .. (289,135.28) .. controls (292.07,135.28) and (294.55,137.77) .. 
 (294.55,140.84) .. controls (294.55,143.91) and (292.07,146.39) .. 
 (289,146.39) .. controls (285.93,146.39) and (283.45,143.91) .. 
 (283.45,140.84) -- cycle ;

\draw (243,140.4) node [anchor=north west][inner sep=0.75pt]{$r$};
\draw (218,98.4) node [anchor=north west][inner sep=0.75pt]{$r$};
\draw (298,134.4) node [anchor=north west][inner sep=0.75pt]{$M$};
\draw (271,63.4) node [anchor=north west][inner sep=0.75pt]{$N$};
\draw (245,11.4) node [anchor=north west][inner sep=0.75pt]{$\Delta\alpha $};
\draw (236.58,121.82) node [anchor=north west][inner sep=0.75pt]{$\Delta\alpha $};
\draw (268.55,92.86) node [anchor=north west][inner sep=0.75pt][rotate=-56.74]{$\Delta S$};

\end{tikzpicture}