# Elasticity: Definition, Examples, & Illustrations

• Tam Le
In summary, elasticity is the measure of the tendency of an object to resist deformation and its ability to return to its original form/shape after removing the applied force. Both definitions are correct and are related to stiffness and Young's modulus. The confusion may come from the fact that Young's modulus is also called "modulus of elasticity" or "elastic modulus". However, a large value of Young's modulus means that the material is stiffer, not "more elastic". The terms elastic, plastic, and brittle are subjective qualitative descriptions of material properties. Elasticity and plasticity are mutually exclusive concepts. In elastic collisions, energy is conserved while in plastic collisions, energy is used towards deformation.
Tam Le
I read somewhere that elasticity is the measure of the tendency of an object to resist deformation (similar to how inertia resists motion). I also read elsewhere that elasticity is the measure of how well an object returns to its shape/form after removing the applied force.

Which definition is correct? Are they two sides of the same coin: An object with a high elasticity value would be tough to deform, but it would also be able to return to its original form/shape more or less accurately. An example or picture illustrating the concept would be preferable.

Those two definitions do not contradict each other so both of them are correct.

An object tries to resist deformation while it is put under stress (one or more forces are acting - trying to deform it) and that same object will try to return to it's original form/shape(given that no plastic deformations occur) after the aforementioned forces stop acting on it.

Tam Le
Thank you for your explanation (just don't hackMe ).

Elasticity isn't a measure if how well an object can return to it's initial form, if it doesn't return to it's initial shape it isn't elastic, it's plastic in that case, elasticity is the ability to return to initial state, all materials exhibit elastic behavior, then at a certain exerted force they become plastic

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The confusion may come from the fact that Young's modulus (Y or E) is also called "modulus of elasticity" or "elastic modulus".
However a large value of E means that the material is stiffer and not "more elastic".

If you are looking for some kind of a measure of how elastic a body is, you may look at how much can be deformed before becoming non-elastic. This may be described as "yield point" or "yeld strength" (if the stress is measured).

That makes sense. Thank you A.T.

Noctisdark said:
... all materials exhibit elastic behavior, then at a certain exerted force they become plastic
Just wanted to query this point. Do brittle materials exhibit plasticity? I just had the notion that brittle materials are elastic up to the point of failure.
Just looking at WikiP I see they say that, brittle materials exhibit little or no plastic deformation.

And as far as the foregoing discussion is concerned, I had not come across the idea that terms like elastic, plastic and brittle were defined. I have always taken them as mere qualitative descriptions of the properties of materials.

Yes all material can become plastic, but that plastic zone is very tiny for brittle one, meaning once.it become plastic, it can break easily by adding force

This is the first I have heard of plastic in physics, thanks for the heads-up everyone!

Elasticity and plasticity are mutually exclusive, correct? If a collision is perfectly elastic no plasticity can be exhibited and a perfectly plastic collision (ignoring plausibility) all of the energy would be used towards deformation.

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You are mixing the ideas of elastic/plastic material properties and elastic/plastic collisions. I am guessing that you are thinking about rigid body collisions in which elastic means that energy is conserved. Plastic is everything else.

## What is elasticity?

Elasticity is a measure of how responsive a quantity is to a change in another quantity. In other words, it is a measure of how much a variable changes in relation to a change in another variable.

## What are some examples of elasticity?

Some examples of elasticity include price elasticity of demand, income elasticity of demand, and cross-price elasticity of demand. These measures are used to understand how changes in price, income, or the price of related goods affect the demand for a particular product.

## How is elasticity calculated?

Elasticity is calculated by taking the percentage change in the variable of interest and dividing it by the percentage change in the other variable. For example, price elasticity of demand is calculated by dividing the percentage change in quantity demanded by the percentage change in price.

## What are the different types of elasticity?

There are three main types of elasticity: price elasticity, income elasticity, and cross-price elasticity. Within each type, there are specific measures such as price elasticity of demand, price elasticity of supply, income elasticity of demand, and cross-price elasticity of demand.

## Why is elasticity important?

Elasticity is important because it helps us understand how changes in one variable affect another variable. This is particularly useful for businesses and policymakers in making decisions about pricing, production, and market strategies. Elasticity also helps us understand consumer behavior and market trends.

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