Picture shows a photograph of two stilt walkers in standing position.

Two stilt walkers in standing position. All forces acting on each stilt walker balance out; neither changes its translational motion. In addition, all torques acting on each person balance out, and thus neither of them changes its rotational motion. The result is static equilibrium. (credit: modification of work by Stuart Redler/OpenStax)

Static Equilibrium and Elasticity

Previously, you studied about forces, Newton's laws for translational motion, torques, rotational motion about a fixed axis, etc. You also studied the difference between static and dynamic equilibrium.

In this chapter, we bring together static translational equilibrium and static rotational equilibrium to describe situations related to construction. We will explore answers to some of the questions tackled by contemporary engineers: What type of cables support a suspension bridge? What type of foundation will support a building?

The elastic properties of materials are studied in this chapter. They are important in bioengineering, construction work, civil engineering, etc. Materials may stretch or compress and then return to their original position. These material are good shock absorbers. As you move through this chapter, you will learn more about these properties in various materials.

Watch the following set of videos to learn more about elasticity.

Elastic and non elastic materials Khan Academy

Stress vs. strain Khan Academy

Young's modulus of elasticity Khan Academy

Stress vs. strain curve Khan Academy

Summary

You may want to refer back to this lecture for support on the following concepts:

Elastic and non-elastic materials
Stress and Strain
Young's modulus of elasticity
Stress vs. strain curve