Update MetaPost to Asymptote in Serway and Jewett v4's problem 19.11.

diff --git a/latex/problems/Serway_and_Jewett_4/problem19.11.tex b/latex/problems/Serway_and_Jewett_4/problem19.11.tex
index 74c951848946e7658962ed73a9feb3ad72cc6e60..52473bf79fa920b743b719008ad35a2caed6fa5e 100644 (file)
--- a/latex/problems/Serway_and_Jewett_4/problem19.11.tex
+++ b/latex/problems/Serway_and_Jewett_4/problem19.11.tex
@@ -4,50 +4,43 @@ the electric field is zero.
 $q_1 = -2.50\U{$\mu$C}$ and $q_2 = 6.00\U{$\mu$C}$.
 \end{problem*} % problem 19.11
 
-\empaddtoprelude{
-  pair A, B;
-  A := origin;
-  B := (2cm, 0);
-  C := (-3.6cm, 0);
-  numeric orig_labeloffset;
-  orig_labeloffset := labeloffset;
-  def drawD =
-    label.bot("x", draw_arrow((-2cm,0), (-1cm,0), 4cm, 0pt, black));
-    label.bot("0", draw_ltic(A, -90, 0, 10pt, 0pt, black));
-    label.bot("1m", draw_ltic(B, -90, 0, 10pt, 0pt, black));
-    draw_ncharge(A, 4pt);
-    draw_pcharge(B, 6pt);
-    labeloffset := 8pt;
-    label.top(btex $q_1$ etex, A);
-    label.top(btex $q_2$ etex, B);
-    labeloffset := orig_labeloffset;
-  enddef;
-}
-
 \begin{nosolution}
 \begin{center}
-\begin{empfile}[4ns]
-\begin{emp}(0cm,0cm)
-  drawD;
-\end{emp}
-\end{empfile}
+\begin{asy}
+import ElectroMag;
+
+real u = 2cm;
+draw_ijhat();
+Charge a = aCharge(q=-2.5, "$q_1$");  a.draw();
+Charge b = aCharge(q=6.0, (1u, 0), "$q_2$");  b.draw();
+Distance dab = Distance(a.center(), b.center(), offset=12pt, L="$1\U{m}$");
+dab.draw();
+\end{asy}
 \end{center}
 \end{nosolution}
 
 \begin{solution}
 \begin{center}
-\begin{empfile}[4]
-\begin{emp}(0cm,0cm)
-  drawD;
-  draw_tic(A, -180, 0, 4.5cm, 0pt, black); % extend x axis
-  label.top(btex $r_1$ etex, draw_length(A, C, 20pt));
-  label.bot(btex $r_2$ etex, draw_length(C, B, 20pt));
-  label.bot(btex $E_1$ etex, draw_Efield(A, C, -10pt));
-  label.bot(btex $E_2$ etex, draw_Efield(B, C, 10pt));
-  dotlabel("",C);
-\end{emp}
-\end{empfile}
+\begin{asy}
+import ElectroMag;
+
+real u = 2cm;
+draw_ijhat();
+Charge a = aCharge(q=-2.5, "$q_1$");  a.draw();
+Charge b = aCharge(q=6.0, (1u, 0), "$q_2$");  b.draw();
+Distance dab = Distance(a.center(), b.center(), offset=12pt, L="$1\U{m}$");
+dab.draw();
+pair c = (-1.82u, 0);
+Distance dac = Distance(c, a.center(), offset=24pt, L="$r_1$");  dac.draw();
+Distance dbc = Distance(c, b.center(), offset=36pt, L="$r_2$");  dbc.draw();
+Charge cs[] = {a, b};
+CoulombEFields(c, cs, scale=u, unit=u);
+dot(c);
+\end{asy}
 \end{center}
+%  label.bot(btex $E_1$ etex, draw_Efield(A, C, -10pt));
+%  label.bot(btex $E_2$ etex, draw_Efield(B, C, 10pt));
+%  dotlabel("",C);
 
 First, we need a coordinate system.  Let $q_1$ be the origin
 ($x_1=0$), and $q_2$ be at $x_2 = 1.00\U{m}$.