Manipulate[
BarChart[{Labeled[v1,v1,{0.5,v1+0.5}],Labeled[v2,v2,{0.5,v2+0.5}],Labeled[(v1+v2),(v1+v2),{0.5,(v1+v2)+0.5}],Labeled[(v1+v2)/(1+ v1 v2),(v1+v2)/(1+ v1 v2),{0.5,((v1+v2)/(1+ v1 v2))+0.5}]},PlotRange->{-0.5,2},ChartLabels->{“v1″,”v2″,”Galileo\nNewton”,”Einstein”},ChartElementFunction->”GlassRectangle”,ChartStyle->”Pastel”,AxesLabel->{“Velocities”,”c”}]
,{v1,0,1},{v2,0,1}]