What is Potential Energy? - Exploring the Types

[PhanthomJay]

PhanthomJay are all energies mechanical?

No. But when any type of energy ...be it chemical, nuclear, or (heaven forbid) mechanical energy (definition 2)...is transferred into or out of the system, it changes the mechanical energy (definition 1) of the system. This follows from conservation of energy law, dE + dU + dK = 0, where dE represents the energy transferred into or out of the system from work done by non-conservative forces.

 

[I-copeland]

i don't understand.
Basically I've heard chemical energy is classified potential and so i want to know (following logic) if it is mechanical and if not then the this could cause the Professor of Logic to spit out his drink.

 

[Somenath]

Chemical energy libeated in a reaction is equivalent to the change in Potential energy due to the force of attraction among the atoms.

 

[Somenath]

Whats ur point?

I mean the transformation relations between Potential and other energies are so designed that they seem to be equal.

 

[I-copeland]

I mean the transformation relations between Potential and other energies are so designed that they seem to be equal.

I see, well I'm not inquiring if they're equal but if the energetic classification for chemical energy is mechanical? Jolly good.

 

[member 392791]

Energy is energy is energy? It's all the same concept, just manifests itself in different phenomenons, right?

 

[I-copeland]

Chemical energy libeated in a reaction is equivalent to the change in Potential energy due to the force of attraction among the atoms.

So it is mechanical...

 

[I-copeland]

Energy is energy is energy? It's all the same concept, just manifests itself in different phenomenons, right?

U call yourself a scientist!??

 

[member 392791]

No, I'm actually curious about the answer to your question, but I'm just basing my idea strictly on the definitions provided by wikipedia and how I interpret them. I have pondered myself as to what mechanical energy is, and this is what is provided:

''In physics, mechanical energy is the sum of potential energy and kinetic energy present in the components of a mechanical system.''

Now, this statement doesn't give any definition as to what a mechanical system is, so I wikipedia that and find:

''A mechanical system manages power to accomplish a task that involves forces and movement''

Ok, so in all the previous phenomenon discussed (chemical energy, electrical energy, etc) there are forces involved and movement, so I am prone to believe, based strictly on these definitions, that they (chemical or electrical phenomenon) are also mechanical systems. If someone reputable is able to tell me otherwise, I am all ears. That is why I joined this discussion, whether to confirm my thoughts or for them to be ripped to shreds is indifferent to me as long as I learn what it actually means.

 

[I-copeland]

dude! me to.

 

[Doc Al]

Ok, so in all the previous phenomenon discussed (chemical energy, electrical energy, etc) there are forces involved and movement, so I am prone to believe, based strictly on these definitions, that they (chemical or electrical phenomenon) are also mechanical systems

When we talk about 'mechanical energy' we usually mean energy due to an object's motion (kinetic energy) and position (potential energy). The kinetic energy meant here is macroscopic kinetic energy--due to the object's motion as a whole, not its internal molecular motion. Similarly, the potential energy included in 'mechanical energy' is due to the object's macroscopic position--it excludes all sorts of internal energy such as chemical energy.

 

[member 392791]

So mechanical energy is used to describe only what its name implies, mascroscopic objects? No electrons for electrical energy (because the electrons do have mass)?

 

[Doc Al]

So mechanical energy is used to describe only what its name implies, mascroscopic objects?

Usually, yes. But it depends on the context.

No electrons for electrical energy (because the electrons do have mass)?

When the electron is the object, then you can consider its electrostatic potential energy (when with another charged particle) as part of the mechanical energy of the system.

But if your system is a ball throw up in the air, then all that matters is its macroscopic kinetic energy and the gravitational PE when considering its mechanical energy. (At least that is the usual context.)

 

[Drakkith]

So mechanical energy is used to describe only what its name implies, mascroscopic objects? No electrons for electrical energy (because the electrons do have mass)?

In any macroscopic non-electrical machine the electrons are too small to matter, so any energy they have isn't included. In electrical machines, which specifically deal with moving electrons, this is obviously different. For mechanical energy, think in terms of classical machines and what we build from them. Something like a clock that uses a pendulum and weights is pure mechanical energy, no electrical or chemical.

 

[I-copeland]

So u get "macroscopic mechanical energy" and "microscopic mechanical energy"?

 

[I-copeland]

where did everyone go :(

 

[Drakkith]

where did everyone go :(

Nowhere.

 

[PhanthomJay]

Nowhere.

Which is the same place this thread is going.

 

[Drakkith]

Copeland, there is no "exact answer". Could you consider an electron to have mechanical energy? Sure, in the right context and as long as you make it clear that's what you are doing.

 

[I-copeland]

hmmm well i wanted to connect different levels of mechanical energy to the the different levels of the energy hierarchy (entropy).

 

[Drakkith]

hmmm well i wanted to connect different levels of mechanical energy to the the different levels of the energy hierarchy (entropy).

I see no reason you cannot do this. Just realize that it probably won't be as "exact" as you were hoping.

 

[FissX]

Mechanical energy requires organization. It is part of a mechanical system in which power management accomplishes a task. Energy may be stored in systems without being present as matter, or as kinetic or electromagnetic energy. But until an outside force utilizes potential energy, mechanical energy will not exist. Refer to the laws of conservation of energy.

 

[I-copeland]

seems like ur saying potential energy isn't mechanical :(

 

[Drakkith]

seems like ur saying potential energy isn't mechanical :(

From wikipedia:

In physics, mechanical energy is the sum of potential energy and kinetic energy present in the components of a mechanical system.

I think that sums it up. If you stick to that you can't go wrong.

 

[FissX]

Mechanical energy is not potential energy. It is the conduit or storage of energy of a system with a set task. As it is present in the system, only after the conversion of potential energy, is it referred to as mechanical. Drakkith is correct. Notice the part that says "components of a mechanical system".

 

[Doc Al]

Mechanical energy is not potential energy. It is the conduit or storage of energy of a system with a set task. As it is present in the system, only after the conversion of potential energy, is it referred to as mechanical. Drakkith is correct. Notice the part that says "components of a mechanical system".

You seem to be saying that potential energy is not mechanical energy, which is incorrect. Please refer to the wiki definition quoted by Drakkith. There really isn't much more to it. It's just a term of convenience.

 

[FissX]

There is a difference between potential energy existing IN mechanical energy and potential energy actually BEING mechanical energy. They are not one in the same. Mechanical energy cannot exist without potential energy. But potential energy can exist without mechanical energy.

Because I send electricity into a copper wire (example) does not mean the copper wire is also the source of energy. It is a conduit with which potential energy is stored (short version). Mechanical energy is the "copper wire" in the sense that it is an organized mechanical system with a set task.

 

[Doc Al]

There is a difference between potential energy existing IN mechanical energy and potential energy actually BEING mechanical energy. They are not one in the same. Mechanical energy cannot exist without potential energy. But potential energy can exist without mechanical energy.

Because I send electricity into a copper wire (example) does not mean the copper wire is also the source of energy. It is a conduit with which potential energy is stored (short version). Mechanical energy is the "copper wire" in the sense that it is an organized mechanical system with a set task.

I have no idea what you think 'mechanical energy' is or what you are trying to say.

Try this: Toss a ball into the air. Define the mechanical energy of the system. Is it conserved? Why or why not?

 

[Drakkith]

There is a difference between potential energy existing IN mechanical energy and potential energy actually BEING mechanical energy. They are not one in the same. Mechanical energy cannot exist without potential energy. But potential energy can exist without mechanical energy.

Because I send electricity into a copper wire (example) does not mean the copper wire is also the source of energy. It is a conduit with which potential energy is stored (short version). Mechanical energy is the "copper wire" in the sense that it is an organized mechanical system with a set task.

I don't believe that would be mechanical energy, but electrical energy. Furthermore, given the definition of mechanical energy, I don't agree with your view that potential energy isn't mechanical energy. It doesn't HAVE to be mechanical energy, but it is part of it when appropriate.

 

[I-copeland]

Is there a simple way to understand the logic of the sequence of the energetic quality hierarchy?

Thanks