Elasticity vs Plasticity and Hooke’s Law - Physics | Mocomi Kids
Robert Hooke investigated how springs and elastic materials stretch. As an equation, Hooke's Law says that the force applied in newtons (or. In this article, I will be looking at the tensile strength, stiffness, Hooke's law, how to use Hooke's law, Young Modulus (E) and example questions. The theory for. Poems Poems . Difference between plasticity and elasticity Hooke's Law proposes that the amount of elongation of a spring is directly proportional to the In other words, Young's modulus is a measure of the flexibility of a given material.
Other elastic calculations usually require the use of one additional elastic property, such as the shear modulusbulk modulus or Poisson's ratio. Any two of these parameters are sufficient to fully describe elasticity in an isotropic material. Linear versus non-linear[ edit ] Young's modulus represents the factor of proportionality in Hooke's lawwhich relates the stress and the strain.
Hooke's Law & the Spring Constant: Definition & Equation
However, Hooke's law is only valid under the assumption of an elastic and linear response. Any real material will eventually fail and break when stretched over a very large distance or with a very large force; however all solid materials exhibit nearly Hookean behavior for small enough strains or stresses. If the range over which Hooke's law is valid is large enough compared to the typical stress that one expects to apply to the material, the material is said to be linear.
Otherwise if the typical stress one would apply is outside the linear range the material is said to be non-linear.
Steelcarbon fiber and glass among others are usually considered linear materials, while other materials such as rubber and soils are non-linear. However, this is not an absolute classification: For example, as the linear theory implies reversibilityit would be absurd to use the linear theory to describe the failure of a steel bridge under a high load; although steel is a linear material for most applications, it is not in such a case of catastrophic failure.
In solid mechanicsthe slope of the stress—strain curve at any point is called the tangent modulus. It can be experimentally determined from the slope of a stress—strain curve created during tensile tests conducted on a sample of the material. Elasticity is a property of a material which allows it to return to its original shape or length after being distorted.
Some materials are not at all elastic -- they are brittle and will snap before they bend or stretch.
Young's modulus - Wikipedia
Others, like rubber, for example, will stretch a long way without significant warping or cracking. This is because the materials contain long chain molecules that are wrapped up in a bundle and can straighten out when stretched. Those are the materials we choose for things like waistbands. But in physics we like numbers.
One important number that relates to elasticity is the spring constant. The spring constant is a number that represents how much force it takes to stretch a material -- materials with larger spring constants are stiffer. So these are our properties to describe the stretchiness of materials -- elasticity and the spring constant. But what happens when you're in the process of stretching out a rubber band? Do you need more force at first and less once you've stretched part way?
Perhaps it's the other way around?
The relationship could be almost anything -- linear, quadratic, variable