We explain what is the elasticity in physics and how is the formula of this property. In addition, examples and what are the elastic materials.
What is elasticity in physics?
When in physics we refer to elasticity , we mean the property of certain materials to be deformed under an external force that acts on them, and then recover their original form when said force disappears. This type of behavior is known as reversible deformation or shape memory.
Not all materials are elastic, of course, and those that break, fragment or remain deformed after the action of the external force, are simply not elastic at all.
The principles of elasticity are studied by the mechanics of deformable solids , according to the Theory of Elasticity, which explains how a solid deforms or moves in response to external forces that affect it.
Thus, when these deformable solids receive said external force, they deform and accumulate within them an amount of elastic potential energy, and therefore also of internal energy.
Said energy, once the deforming force is removed, will be the one that forces the solid to regain its shape and transforms into kinetic energy , making it move or vibrate.
The magnitude of the external force and the elasticity coefficients of the deformed object will be those that allow to calculate the size of the deformation, the magnitude of the elastic response and the tension accumulated in the process.
Formula of elasticity in physics
When a force is applied on an elastic material, it is deformed or compressed. For mechanics , the important fact is the amount of force applied per unit area, which we will call effort ( σ ).
We will call the degree of stretching or compression of the matter deformation ( ϵ ) and calculate it by dividing the length of movement of the solid (ΔL) by its initial length (L0), that is: ϵ = ΔL / L 0.
On the other hand, one of the main laws governing the issue of elasticity is Hooke’s Law . This law was formulated in the seventeenth century by physicist Robert Hooke when studying the springs, and realizing that the force needed to shrink them was proportional to the length of the spring.
This law is formulated as follows: F = ˗kx where F is the force, x the length of the understanding or elongation, and k a constant of proportionality (spring constant) expressed in Newtons over meters (N / m).
Finally, the elastic potential energy associated with the force of this law is represented by the formula: Ep (x) = ½. k.x2 .
Examples of elasticity in physics
The elasticity of materials is a property that we test daily. Some examples of this can be:
- Springs . The springs under certain buttons, or that push the toaster’s bread up when ready, operate based on elastic tension: they are compressed and accumulate potential energy, then they are released and regain their shape by throwing up the bread toasted.
- Buttons . The buttons on the TV remote control operate thanks to the elasticity of the material that composes them, since they can be compressed under the force of our fingers, by activating the circuit below, and then recovering their initial position (stop activating the circuit immediately ), ready to press again.
- The gum . The resin from which the gum or chewing gum is made is extremely elastic, to the point that we can compress it between the teeth or expand it by filling it with air and making a pump, expecting that it will retain its more or less original shape.
- Tires . From an airplane, a car, a motorcycle, they operate based on the elasticity of the rubber, which once inflated with air , can withstand the enormous weight of the entire vehicle and slightly deform, but without losing its shape memory, so it exerts a resistance and keeps the vehicle suspended.
The elastic materials, those capable of recovering their original shape after suffering a partial or total deformation , are numerous and we can list some of them, such as: rubber, rubber, nylon , lycra, latex, chewing gum, wool, silicone, foam rubber , graphene, fiberglass, plastic , rope, among others. These types of materials are extremely useful in the manufacturing industry, since from them you can make endless applications and objects of practical use.