An Engineer is waring a knit kneck tie. He pulls on the tie and says "Poisson's ratio"


















If you don't get it, Poisson's ratio n is the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force. Tensile deformation is considered positive and compressive deformation is considered negative. The definition of Poisson's ratio contains a minus sign so that normal materials have a positive ratio. n = - etrans / elongitudinal


If you still don't get it, your normal. Otherwise your a geek.