Coefficient of Elasticity

Ratio of the unit-stre to the unit-elongation when the elastic limit is not exceeded; or force per unit of section which would stretch a bar to double its length if its elasticity were not impaired. If P be the tensile force which stretches a bar, A the area of its cro -section, 1 its length and s its stretch caused by the tension, the coefficient of elasticity is E-PS-Pl. The mean value of E for Al As timber is 1,500,000 pounds per sq. in., for cast iron 15,000,000, for wrought iron 25,000,000, and for steel 30,000,000.