t0 = 0;
\[CurlyPhi]0 = 0.25;
g = 9.81;
l = 1.45;
\[CurlyPhi]10 = 0;
stepsize = 0.01;

\[CurlyPhi]2[\[CurlyPhi]_] := (3*Sin[\[CurlyPhi]]*g)/(2*l)

euler := Module[{ans, t, \[CurlyPhi], \[CurlyPhi]1}, 
  		ans = {{t0, \[CurlyPhi]0}}; 
		\[CurlyPhi] = \[CurlyPhi]0;
  		t = t0;
  		\[CurlyPhi]1 = \[CurlyPhi]10;
  		While[\[CurlyPhi] < 1.5708,
			\[CurlyPhi]1 = \[CurlyPhi]1 + stepsize*\[CurlyPhi]2[\[CurlyPhi]];
   			\[CurlyPhi] = \[CurlyPhi] + stepsize*\[CurlyPhi]1; 
   			t = t + stepsize; 
			ans = Append[ans, {t, \[CurlyPhi]}] ];
		ans]

eulerans1 = Drop[euler, -1];

Last[eulerans1]

grapheuler1 = ListPlot[eulerans1, AxesLabel -> {"t", "\[CurlyPhi]"}, PlotStyle -> {PointSize[0.01]}, GridLines -> Automatic]

h = 0.0001;

times = Module[{\[CurlyPhi]0, bns}, bns = {{0.2, 0.8819999999999192}};
   \[CurlyPhi]0 = 0.22;
   While[\[CurlyPhi]0 < 1.32,
    bns = Append[
      bns,
      {\[CurlyPhi]0, Last[Drop[Module[
          {ans, t, \[CurlyPhi], \[CurlyPhi]1},
          ans = {t0};
          \[CurlyPhi] = \[CurlyPhi]0;
          t = t0;
          \[CurlyPhi]1 = \[CurlyPhi]10;
          While[
           \[CurlyPhi] < 1.5708,
           \[CurlyPhi]1 = \[CurlyPhi]1 + h*\[CurlyPhi]2[\[CurlyPhi]];
           \[CurlyPhi] = \[CurlyPhi] + h*\[CurlyPhi]1;
           t = t + h;
           ans = Append[ans, t] ]; ans], -1]]}
      ];
    \[CurlyPhi]0 = \[CurlyPhi]0 + 0.02]; bns];

ListPlot[times, AxesLabel -> {"\[CurlyPhi]0", "T"}, PlotStyle -> {PointSize[0.01]}, GridLines -> Automatic]

acceleration = 1.45*\[CurlyPhi]2[1.5708]