) or the modulus of elasticity
, is defined as
Modulus of elasticity = stress / strain
The modulus has the same units as stress. A large modulus means that a large stress is requird to produce a given strain - the object is rigid
Accordingly, Y = ( F/A ) / ( Δ/L0 ) = FL0 / AΔL
Its SI unit is Pa. Unlike the constant k in Hooke's Law, the value Y depends only on the material of the wire or rod], and not on its dimensions or configuration. Consequenty, Young's modulus is an important basic measure of the mechanical behavior of materials.