Elastic potential energy: Difference between revisions

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[[Category:Done 2016-04-30]]  
[[Category:Done 2021-10-29]]
[[Category: Translated to French]]
[[fr:Énergie potentielle élastique]]
[[File:Mxcpcrossbow-elastic-potential.gif|200px|framed|Figure 1. Elastic potential energy stored by a spring.<ref>Wilson, Tracy. (2014, Aug. 14). ''How Crossbows Work'' [Online]. Available: http://science.howstuffworks.com/crossbow2.htm</ref>]]
[[File:Mxcpcrossbow-elastic-potential.gif|200px|framed|Figure 1. Elastic potential energy stored by a spring.<ref>Wilson, Tracy. (2014, Aug. 14). ''How Crossbows Work'' [Online]. Available: http://science.howstuffworks.com/crossbow2.htm</ref>]]
<onlyinclude>The [[Potential energy]] stored in a spring (or any similar object) is known as the [[elastic potential energy]].  It is stored by the deformation of an elastic material such as the spring in Figure 1.</onlyinclude><ref name=Book1>Landau, L.D. and Lifshitz, E. M., ''Theory of Elasticity,'' 3rd ed. Oxford, England: Butterworth Heinemann, 1986, Ch. 2.</ref>
<onlyinclude>[[Elastic potential energy]] is the [[potential energy]] stored by the deformation of an elastic material, such as a spring seen in Figure 1.</onlyinclude><ref name=Book1>Landau, L.D. and Lifshitz, E. M., ''Theory of Elasticity,'' 3rd ed. Oxford, England: Butterworth Heinemann, 1986, Ch. 2.</ref>


== Background ==
== Background ==
The [[energy]] stored in a spring depends on the distance the spring is deformed (stretched or compressed) and the spring constant, which defines the amount of force required to deform a spring by a certain length (the [[work]] done on the spring).<ref name=Knight>R. D. Knight, "Springs," in ''Physics for Scientists and Engineers: A Strategic Approach,'' 2nd ed. San Francisco: Pearson Addison-Wesley, 2008, pp. 281-284.</ref> The ability to get energy out depends on the material's [[elasticity]].
The ability to transfer energy to this form depends on a material's [[elasticity]]. The [[energy]] stored in a spring depends on the:
*Distance the spring is deformed (stretched or compressed.)  
*Spring constant. This constant is the amount of [[force]] required to stretch or compress a spring by one meter.<ref name=Knight>R. D. Knight, "Springs," in ''Physics for Scientists and Engineers: A Strategic Approach,'' 2nd ed. San Francisco: Pearson Addison-Wesley, 2008, pp. 281-284.</ref>  


Elastic potential energy is given by the equation:<ref name="Knight"/>
Elastic potential energy is given by the equation:<ref name="Knight"/>


<m> E_{elastic}= \frac{1}{2}{k}{x^2}</m> where,
<math>E_{elastic}= \frac{1}{2}{k}{x^2}</math> where


• <m> E_{elastic}</m>: elastic potential energy ([[Energy|Joules]], J)
• <math>E_{elastic}</math>: elastic potential energy ([[Energy|Joules]], J)


• <m> k </m>: elastic constant ([[Force|Newtons]] per meter, N/m)
• <math>k</math>: spring constant ([[Force|Newtons]] per meter, N/m)


• <m> x </m>: distance of stretching ([[meter]]s, m)
• <math>x</math>: distance from original (equilibrium) position ([[meter]]s, m)


The elastic properties of a spring depends on both shape and the material of the spring. Therefore, the elastic constant is different for every object. Elastic potential energy increases with the constant of the spring and with the distance stretched.<ref name=Book1/>
The elastic properties of a spring depend on both the shape and the material of the spring. Therefore, the spring constant is different for every object.


== Application ==
== Application ==
A spring is used to store elastic potential energy in many mechanical devices (like the shock absorbers in cars). This energy can be used in many ways since the spring can remain in its compressed or stretched state for extended periods of time without dissipating energy.<ref name="Knight"/>
Because a spring can remain in a compressed or stretched state for extended periods without dissipating energy, elastic potential energy is fundamental to many mechanical devices,<ref name="Knight"/> such as shock absorbers in cars.


Spring potential can also be utilized in control systems or mechanical systems to reduce the impact of disturbance, such as in motor vehicles. In vehicles, the shock absorbers are springs that absorb the energy created by hitting bumps in the road, preventing the energy from disrupting the passenger compartment of the vehicle. Another use of spring potential in vehicles is in [[Regenerative braking|regenerative braking systems]], where the stored energy is used to give the vehicle a small power boost.
This potential can also be utilized in control or mechanical systems to reduce the impact of disturbance, such as in motor vehicles. In vehicles, shock absorbers aim to reduce the impact on passengers by absorbing [[force]]s caused by driving on bumpy roads. Another use of elastic potential energy in vehicles is in [[Regenerative braking|regenerative braking systems]], where stored energy is used to give the vehicle a small power boost.


==Elastic vs. plastic deformation==
==Elastic vs. plastic deformation==
Changing the shape of a system takes energy. If the energy comes back out when the pressures and forces are released, that deformation is called elastic deformation (and makes elastic potential energy). Plastic deformation is the energy that is put into the system that doesn't come back out; for example, when two cars collide, much of their energy goes into changing the shape of the cars.<ref>R. D. Knight, "Inelastic collisions," in ''Physics for Scientists and Engineers: A Strategic Approach,'' 2nd ed. San Francisco: Pearson Addison-Wesley, 2008, pp. 284-287.</ref>
''Elastic deformation'' is a type of deformation that occurs when the energy used to change the shape of an object is equally output when pressures and forces are released. For example, when you pull a spring, the spring will return to its original shape when released (energy input equals energy output.) This is what allows objects to have ''elastic potential energy''.  


Plasticity means that when something is stretched, it stays stretched. When an object stays stretched (or bent), that process is called plastic deformation. When the material goes back to its original form, that's elastic deformation.<ref name=Hawkes>Hawkes et al, "Deformation and Elasticity," in ''Physics for Scientists and Engineers'' 1st ed. Toronto: Cengage, 2014, pp. 265-268.</ref>
Plastic deformation is the type of deformation that occurs when the energy used to deform an object is not equal to energy output. The object does not return to its original shape. For example, when two cars collide, much of their [[kinetic energy]] is transferred into new forms and is used to permanently change the shape of the cars.<ref>R. D. Knight, "Inelastic collisions," in ''Physics for Scientists and Engineers: A Strategic Approach,'' 2nd ed. San Francisco: Pearson Addison-Wesley, 2008, pp. 284-287.</ref>  


All springs have some plastic deformation, so some energy is always lost. Plastic deformation causes the [[atom]]s to speed up in the spring, raising the [[temperature]] of the material (similar to, but different from [[friction]]), which is why the hoods of cars are quite hot after a car accident. Elastic potential energy is the energy that comes back out, so that doesn't increase the temperature.
Plasticity means that when something is stretched, it stays stretched. When an object stays stretched (or bent), that process is called ''plastic deformation''. When the material goes back to its original form, ''elastic deformation'' has occurred.<ref name=Hawkes>Hawkes et al, "Deformation and Elasticity," in ''Physics for Scientists and Engineers'' 1st ed. Toronto: Cengage, 2014, pp. 265-268.</ref>


To learn more about elastic potential energy, please see [http://hyperphysics.phy-astr.gsu.edu/hbase/pespr.html hyperphysics].
All springs have some degree of plastic deformation. Some energy is ''always'' transferred to new forms, such as [[thermal energy]]. Plastic deformation causes the [[atom]]s in the spring to speed up, raising the [[temperature]] of the material (similar to, but different from [[friction]].) This is why the hoods of cars are quite hot after a car accident. Elastic potential energy does not transfer into new forms, so it does not increase the temperature.


== Reference ==
==Phet Simulation==
The [http://phet.colorado.edu/ University of Colorado] has graciously allowed us to use the following Phet simulation. Explore this simulation to see how gravitational potential energy, elastic potential energy, and kinetic energy are related in elastic systems.
 
<html>
<iframe src="https://phet.colorado.edu/sims/html/masses-and-springs/latest/masses-and-springs_en.html" width="800" height="600" scrolling="no" allowfullscreen></iframe>
</html>
 
== For Further Reading ==
For further information please see the related pages below:
*[[Elasticity vs plasticity]]
*[[Mechanical energy]]
*[[Kinetic energy]]
*[[Potential energy]]
*[[Force]]
*Or explore a [[Special:Random|random page]]
*One can also visit [http://hyperphysics.phy-astr.gsu.edu/hbase/pespr.html hyperphysics].
 
 
== References ==
{{reflist}}
{{reflist}}
[[Category:Uploaded]]
[[Category:Uploaded]]

Latest revision as of 19:47, 20 December 2021

Figure 1. Elastic potential energy stored by a spring.[1]

Elastic potential energy is the potential energy stored by the deformation of an elastic material, such as a spring seen in Figure 1.[2]

Background

The ability to transfer energy to this form depends on a material's elasticity. The energy stored in a spring depends on the:

  • Distance the spring is deformed (stretched or compressed.)
  • Spring constant. This constant is the amount of force required to stretch or compress a spring by one meter.[3]

Elastic potential energy is given by the equation:[3]

[math]E_{elastic}= \frac{1}{2}{k}{x^2}[/math] where

[math]E_{elastic}[/math]: elastic potential energy (Joules, J)

[math]k[/math]: spring constant (Newtons per meter, N/m)

[math]x[/math]: distance from original (equilibrium) position (meters, m)

The elastic properties of a spring depend on both the shape and the material of the spring. Therefore, the spring constant is different for every object.

Application

Because a spring can remain in a compressed or stretched state for extended periods without dissipating energy, elastic potential energy is fundamental to many mechanical devices,[3] such as shock absorbers in cars.

This potential can also be utilized in control or mechanical systems to reduce the impact of disturbance, such as in motor vehicles. In vehicles, shock absorbers aim to reduce the impact on passengers by absorbing forces caused by driving on bumpy roads. Another use of elastic potential energy in vehicles is in regenerative braking systems, where stored energy is used to give the vehicle a small power boost.

Elastic vs. plastic deformation

Elastic deformation is a type of deformation that occurs when the energy used to change the shape of an object is equally output when pressures and forces are released. For example, when you pull a spring, the spring will return to its original shape when released (energy input equals energy output.) This is what allows objects to have elastic potential energy.

Plastic deformation is the type of deformation that occurs when the energy used to deform an object is not equal to energy output. The object does not return to its original shape. For example, when two cars collide, much of their kinetic energy is transferred into new forms and is used to permanently change the shape of the cars.[4]

Plasticity means that when something is stretched, it stays stretched. When an object stays stretched (or bent), that process is called plastic deformation. When the material goes back to its original form, elastic deformation has occurred.[5]

All springs have some degree of plastic deformation. Some energy is always transferred to new forms, such as thermal energy. Plastic deformation causes the atoms in the spring to speed up, raising the temperature of the material (similar to, but different from friction.) This is why the hoods of cars are quite hot after a car accident. Elastic potential energy does not transfer into new forms, so it does not increase the temperature.

Phet Simulation

The University of Colorado has graciously allowed us to use the following Phet simulation. Explore this simulation to see how gravitational potential energy, elastic potential energy, and kinetic energy are related in elastic systems.

For Further Reading

For further information please see the related pages below:


References

  1. Wilson, Tracy. (2014, Aug. 14). How Crossbows Work [Online]. Available: http://science.howstuffworks.com/crossbow2.htm
  2. Landau, L.D. and Lifshitz, E. M., Theory of Elasticity, 3rd ed. Oxford, England: Butterworth Heinemann, 1986, Ch. 2.
  3. 3.0 3.1 3.2 R. D. Knight, "Springs," in Physics for Scientists and Engineers: A Strategic Approach, 2nd ed. San Francisco: Pearson Addison-Wesley, 2008, pp. 281-284.
  4. R. D. Knight, "Inelastic collisions," in Physics for Scientists and Engineers: A Strategic Approach, 2nd ed. San Francisco: Pearson Addison-Wesley, 2008, pp. 284-287.
  5. Hawkes et al, "Deformation and Elasticity," in Physics for Scientists and Engineers 1st ed. Toronto: Cengage, 2014, pp. 265-268.