Animation Example part 2

cycloid

Definition

cycloid[t_] := {t-Sin[t],1-Cos[t]};
baseline = Line[{{-2,0},{10.5,0}}];
pi = N[Pi];
dots = {PointSize[0.006]};

Do[AppendTo[dots, Point[cycloid[t]]];
   Show[Graphics[{{GrayLevel[.5], Disk[{t,1},1]},
          dots, Line[{{t,1}, cycloid[t]}],  (*spoke*)
          baseline}],   
      AspectRatio->3/12,
      PlotRange->{{-1.5,10.5},{-.5,2.5}}],
       {t, 0., 59/40 2 pi, 2pi/40}]