Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsMacaulay Duration as the Balancing Point of a Seesawhttp://demonstrations.wolfram.com/MacaulayDurationAsTheBalancingPointOfASeesaw/]]>http://demonstrations.wolfram.com/MacaulayDurationAsTheBalancingPointOfASeesaw/