Editing Elastic modulus (section)

== Definition ==
The elastic modulus of an object is defined as the [[slope]] of its [[stress–strain curve]] in the elastic deformation region:<ref>{{cite book| last1 = Askeland| first1 = Donald R.| last2 = Phulé| first2 = Pradeep P.| title = The science and engineering of materials| year = 2006| publisher = Cengage Learning| page = 198| edition = 5th| url = https://books.google.com/books?id=fRbZslUtpBYC&pg=PA198| isbn = 978-0-534-55396-8}}</ref> A stiffer material will have a higher elastic modulus. An elastic modulus has the form:

:<math>\delta \ \stackrel{\text{def}}{=}\  \frac {\text{stress}} {\text{strain}}</math>

where <var>[[stress (physics)|stress]]</var> is the force causing the deformation divided by the area to which the force is applied and <var>[[strain (materials science)|strain]]</var> is the ratio of the change in some parameter caused by the deformation to the original value of the parameter.

Since strain is a dimensionless quantity, the units of <math>\delta</math> will be the same as the units of stress.<ref>{{cite book | last1 = Beer | first1 = Ferdinand P. | last2 = Johnston | first2 = E. Russell | last3 = Dewolf | first3 = John | last4 = Mazurek | first4 = David | title = Mechanics of Materials | url = https://archive.org/details/mechanicsmateria00beer_274 | url-access = limited | year = 2009 | publisher = McGraw Hill | page = [https://archive.org/details/mechanicsmateria00beer_274/page/n78 56] | isbn = 978-0-07-015389-9}}</ref>