Internal Energy

Claimed by Michelle McIntire M06

Main Idea

Internal Energy, as referred to in Intro Physics, is energy within a system. When determining the specifics of internal energy it is best to refer to the real system of the interaction, rather than the point-particle system. The system may consist of internal interactions, such as spring interactions and thermal energy transfer. Internal Energy is any energy in the system other than movement of the center of mass.

Internal Energy is fundamentally Potential Energy, Kinetic Energy, and Rest Energy. Broken down, this includes but is not limited to:

Vibrational Energy: The potential energy of macroscopic springs cannot be modeled as a point particle system, and is often used to represent bonds between atoms in different materials.

Thermal Energy: Thermal Energy is any energy in the form of heat, or changes in energy from heat transfer.

Rotational Energy: Rotational energy is energy of real system about the center of mass.

Chemical Energy: When a person runs, the change in kinetic energy of the runner is often affiliated with a loss in chemical energy.

A Mathematical Model

Determining change in Internal Energy from Change in Kinetic Energy.

Einternal= Ethermal+Erotational+Evibrational+Echemical+...

Because Energy is conserved if change in total Energy is 0, then:

KEi + Einternal= KEf + Einternal

Thus,

Change in Einternal = -Change inKE

A Computational Model

You can use a computational model to track Kinetic Energy of the point-particle system. Using the change in this Kinetic Energy and the Change in Energy due to the surroundings we can determine the change in Internal Energy of a system.

How do we visualize or predict using this topic. Consider embedding some vpython code here Teach hands-on with GlowScript

Examples

Simple

You're pulling a block of mass 20kg. While pulling the block 3 more meters you notice the speed of the block has changed from 8m/s to 15 m/s. What was the change in your internal energy over this period of time?

1) Diagram.File:Diagram1.jpg

Connectedness

1. How is this topic connected to something that you are interested in?

Internal Energy is connected to your everyday life. It fundamentally explains why one must eat (chemical energy) to move (kinetic energy). Internal Energy also describes energy dissipation, and thus is key to solving the Energy crisis.

1. How is it connected to your major?

Internal Energy is extremely important to Mechanical Engineering. It explains the different manners and ways that energy can be stored within a system, and later utilized for Kinetic Energy.

1. Is there an interesting industrial application?

Using our understanding of Internal Energy, we can minimize Energy dissipation, create better longer lasting batteries, create machines that require less power that can store more energy. Applying our understanding of Internal Energy is our best chance at creating something close to perpetual motion, and maximizing energy output of our systems.

History

Many scientists have contributed to our understanding of Internal Energy. From James Joule's work on thermal energy, to Albert Einstein's famous equation for rest energy.

See also

Are there related topics or categories in this wiki resource for the curious reader to explore? How does this topic fit into that context?

Further reading

Books, Articles or other print media on this topic

External links

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References

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