# Local Equilibrium – Lesson 5

How are stresses developed in a body when a load is applied? If the force is applied in only one direction, why do stresses develop in different directions and contribute to different terms in the stress tensor?

As an example, consider a spring under a trampoline. It is fastened on both ends, so it is able to stretch and provide support. The key here is that the forces acting from both ends of the spring balance each other and stretch the spring. But how does one end of the spring sense the force from the other end of the spring?

The answer lies in the key concept of "local equilibrium", which also lets us formulate the governing equations for situations like the trampoline spring. Let's learn these concepts in this lesson.

### Lecture

var option_df_24472 = {"outline":[],"backgroundColor":"#898A8D","forceFit":"true","autoEnableOutline":"false","autoEnableThumbnail":"false","overwritePDFOutline":"false","direction":"1","pageMode":"1","source":"https:\/\/courses.ansys.com\/wp-content\/uploads\/2020\/08\/1.3.5-Local_Equilibrium_rebranded-tp.pdf","wpOptions":"true"}; if(window.DFLIP && DFLIP.parseBooks){DFLIP.parseBooks();}