\begin{tikzpicture}[scale=1,>=latex]
\draw (0,0) circle (1cm);
\fill (0,0) circle (1pt);
\coordinate (p1) at (135:1cm);
\coordinate (p2) at (-45:1cm);
\coordinate (p3) at (p1 |-p2);
\draw (p1) to (p2);
\draw (p1) to (p3) to (p2);
\node (p) at (-1.1,0){\scriptsize 1};
\coordinate (tmp1) at (-1.1,0.7);
\coordinate (tmp2) at (-1.1,-0.7);
\draw [|<-] (tmp1) to (p) ;
\draw [|<-] (tmp2) to (p);
\node [font=\tiny](q) at (0,-1.1){ 1};
\draw [->|] (q)--($(q)+(-0.7,0)$);
\draw [->|] (q)--($(q)+(0.7,0)$);
\node [font=\tiny](q) at (0,-1.5){ 俯视图};
\begin{scope}[yshift=2.2cm]
% \draw (0,0) circle (1cm);
\draw (0,0) +(-1,0) arc (180:360:1cm);
\draw (-1,0) to (1,0);
\fill (0,0) circle (1pt);
\draw (-0.7,0)--+(0,1) -- (0.7,0);
\node [font=\tiny] (q) at (-0.8,0.5) { 1};
\draw [->] (q)--($(q)+(0,-0.5)$);
\draw [->|] (q)--($(q)+(0,0.5)$);
\end{scope}
\begin{scope}[xshift=2.2cm,yshift=2.2cm]
% \draw (0,0) circle (1cm);
\draw (0,0) +(-1,0) arc (180:360:1cm);
\draw (-1,0) to (1,0);
\fill (0,0) circle (1pt);
\draw (-0.7,0)--(0.7,0)--+(0,1)--cycle;
\node [font=\tiny] (q) at (0.8,0.5) { 1};
\draw [->] (q)--($(q)+(0,-0.5)$);
\draw [->|] (q)--($(q)+(0,0.5)$);
\end{scope}
\end{tikzpicture}
