Talk:Potential energy

What about m2?

Common types of potential energy include the gravitational potential energy of an object that depends on

• its mass
• its distance from the center of mass of another object ...

Mass of the other object MIA.

Maybe there's a frame of reference where the mass of m2 is somehow subsumed in such a way that it's implicit in the PE function rather than explicit.

But I suspect this is actually an error in the prose, not a subtle feature of the standard treatment. — MaxEnt 19:27, 25 September 2022 (UTC)

I'm sorry, but I have no clue what you're asking for. Does this have anything to do with the article? Is there some specific change you'd like to make? Zaereth (talk) 19:34, 26 September 2022 (UTC)

I think User:MaxEnt is referring to the second paragraph in the lead. There is a sentence that says potential energy of an object is based on the mass of that object and the distance between the centres of mass of two objects, but says nothing about the mass of the second object (or the universal gravitational constant.) A quick change to the offending sentence in the lead should fix it. Dolphin (t) 03:26, 27 September 2022 (UTC)

I have attempted to eliminate the confusion by erasing unnecessary complexity from the lead. See my diff. Dolphin (t) 06:58, 27 September 2022 (UTC)

Ok. I see. Looks like one of those things that can be read two different ways. When I read it, the term "center of mass" implies the mass of the second object, so saying it again would seem redundant, but I agree it's overly complex for the lede. Your solution seems to fix the problem beautifully. Zaereth (talk) 20:28, 27 September 2022 (UTC)

Semi-protected edit request on 16 March 2023

Following up on an old comment named: "overcomplication" The following sections introduce irrelevant computations that overcomplicate the calculations, but also confuses the reader: "Computing potential energy", "Potential energy for a linear spring", "Potential energy for gravitational forces between two bodies". In these calculations the path integral uses 't' (time) as a path parameter. However: 1. Parametrizing the path is not necessary as it can be integrated as it is. 2. Adding the 'time' concept into this energy focused article makes a mess, because energy, especially for these calculations is completely independent of time. Hanchhanch (talk) 10:21, 16 March 2023 (UTC)

 Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. Actualcpscm (talk) 10:34, 16 March 2023 (UTC)

Under most circumstances, I would probably agree with you. Energy is a unit of quantity, similar to measurements of distance, area, and volume, so it is really independent of time. For example, a capacitor charged to one joule of energy is the same regardless of charging time. When time is factored in, it becomes a measurement of intensity or (to some degree) density. If I release that one-joule capacitor in one second, it's one watt of power. If I release it in one microsecond, it's a million watts of power, but either way only one joule of work gets done.

Now, I don't understand the math unless it's explained in purely mechanical terms --and in plain English-- which mathematicians are typically not very good at. Math is a different language... an alien language. However, I do understand the mechanics enough to know that different calculations for energy require different factors, and in the cases you're describing one of the primary factors they're using is velocity. Because velocity is a product of distance and time, it seems to me that it would be an unavoidable factor in those equations as well.

As an example, take a helicopter. It can fly to a certain altitude, and thereby gain potential energy. It can hover at that altitude, but doing so requires it to maintain a constant climbing speed of 32 feet per second, which is the speed required to constantly fight the restoring force of gravity. To maintain its potential energy it has to constantly burn fuel, and that fuel won't last forever, so time is definitely a factor there.

The question is, what exactly do you see wrong with those equations, and how do you propose we fix them? Zaereth (talk) 21:07, 16 March 2023 (UTC)

An example of a change:

This

$$W=\int _{0}^{t}\mathbf {F} \cdot \mathbf {v} \,dt:=-\int _{0}^{t}kxv_{x}\,dt:=-\int _{0}^{t}kx{\frac {dx}{dt}}dt:=\int _{x(t_{0})}^{x(t)}kx\,dx:={\frac {1}{2}}kx^{2}$$

should be changed to:

$$:W=\int _{0}^{x}\mathbf {F} \cdot \mathbf {x} \,dx=\int _{0}^{x}kx\,dx:={\frac {1}{2}}kx^{2}$$

If you accept this change, I can send here the other changes needed for the other sections. Hanchhanch (talk) 08:23, 13 April 2023 (UTC)

Thanks for clarifying! I don't speak math, so unless you can translate that into English, there's not much I can do to help. There are others here who can read this stuff, and they can probably give you a better answer. Here's the ten-million dollar question, however. Is this your own derivation, or did you get this from a source? If the former, then we can't use it, but if the latter, then you'll need to provide that source. Zaereth (talk) 22:31, 13 April 2023 (UTC)

For a system to have potential energy the system must contain at least two entities

I think that these statements at the start of the article need qualification. "In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors." "Common types of potential energy include the gravitational potential energy of an object, the elastic potential energy of an extended spring, and the electric potential energy of an electric charge in an electric field." I am ok with the spring but surely the references to an object and an electric charge are, at the very least, misleading in that there is an implication of only one entity storing the potential energy? Better the idea of a system of (more than one) . . . . . ? Grove Farcher (talk) 10:41, 18 September 2023 (UTC)

Thanks for your input. The only thing is that, that's how it's normally described in sources. For potential energy, we have two things at play, which is a field (containing a force) and an object (containing the energy provided by that force). Who's to say it's the object that has the energy and not the field? It's simply a matter of convention that we describe the object as containing the energy and the field has the force, but in some reality that is beyond our perception it may be the opposite. And what if there is no other object? For example, a star orbiting a black hole? I know, it's likely that there is some object at the center of the black hole, but no one really knows for sure, which is part of the great mystery of them. We could probably clarify "an object within a gravitational field", which of course describes all objects in the universe. In the spring the energy is actually between the atoms and the forces holding them together. Describing an electric charge (an electron) in an electric field sounds about right. What do you propose we change? Zaereth (talk) 19:34, 18 September 2023 (UTC)

On a side note, the example of electricity is an interesting one to me, because, being a negative particle, the power moves in the opposite direction that the electrons flow, as if in this case the field actually does contain the energy and the object contains the force. Zaereth (talk) 21:32, 18 September 2023 (UTC)

I agree that the first sentence is incorrect and it contradicts the history cited and the third paragraph. Johnjbarton (talk) 19:16, 15 July 2024 (UTC)

Semi-protected edit request on 28 June 2024

In paragraph 2, “the elastic potential energy of an extended spring”: change “extended” to “deformed” in as much as a spring may also be compressed. =avallone (talk) 21:47, 28 June 2024 (UTC)

 Done Tollens (talk) 06:10, 29 June 2024 (UTC)