OT: The 10th Demention

[Raapys]

Kinetic energy is NOT all energy.
A compressed spring isn't hotter or moving any faster than a relaxed one. And that the stretched slingshot dosen't move either... and how about all that chemical potential energy in your car's fuel tank?

You're right, I wasn't thinking.

If you are moving outwards, you lose kinetic energy and speed, but gain potential energy for being higher up and having farther to fall.

I see what you're saying, but I mean, the 'potential energy' you are talking about is a product of gravity. What when an object's speed does exceed the escape velocity; where does the kinetic energy the object loses on the way out, because of gravity, go? Since the object will never be stopped by that mass's gravity once it's reached e.v. that means no potential energy was created but alot of existing energy was lost, or?

[Suicide Junkie]

Its gravitational potential energy. If the object falls down into any gravitational well, that turns back into kinertic energy.

What goes up does *not* have to come back down. That's the point of escape velocity.

You recall those distorted funnel grid paper things that are always used on tv to show gravity fields?
The height represents the potential energy. If the object moves into the depressions, its potential energy is decreasing. In a vaccuum, that pretty much all turns into kinetic energy and back when the object orbits around.

[Fyron]

Raapys said:
But the work formula doesn't cut it. It doesn't even take into account that the force being applied could have ripped apart atomic bindings and the likes even if the object wasn't actually moved.

Perhaps because you can't "rip apart atomic bindings" by pulling on a rope? No amount of force you can apply will overcome the strong nuclear force... Though if you are talking about inter-molecular bonds, those can certainly be broken in the process of applying (thermodynamic) work. But you seem to be thinking of mechanical work...

When you are talking about work, it makes a huge difference which type of work you are talking about. "Work" is a horribly generic word that can mean many different things.

If an object does not move, no mechanical work was done. Mechanical work is purely a derived property of force applied and distance moved. W = F * D is entirely correct, in the mechanical sense of work. Mechanical work does not take heat or other forms of energy transference into account; it only deals with force applied and distance moved.

In the thermodynamic sense of work, you can do work without moving an object. Thermodynamic work is a generalization of the mechanical concept of work; it is a quantity of energy transfered from one system to another. It includes the microscopic thermal motion of particles (aka heat), as well as macroscopic changes to the system (movement, fluid expansion, chemically charging a battery, etc.).

Lets say you decide to push on a wall, which is sturdy enough to resist all of your efforts. Was work performed? No, and yes.

In the mechanical sense, no work was done. The wall was not moved, regardless of how much force you applied. F * 0 is 0.

In the thermodynamic sense, yes, work was done. Your muscles contracted, which required burning up stored carbohydrates and such. This generated heat, which dissipated into your body, the surrounding environment, and perhaps a bit into the wall itself. The force applied on the wall by your hands pushed the wall's molecules ever so slightly inward; this is essentially imparting some kinetic energy from your hands' molecules to the wall's molecules, which in turn is rapidly converted into potential energy. The resulting electromagnetic forces pushed back, resisting any overall change to the structure or location of the wall. In the end, there winds up being no kinetic energy in the wall (when looking holistically at the wall itself). Friction at work (yet another meaning of work... bloody English ). Hopefully I didn't miss anything there, but you get the idea.

The same exact analysis applies to two people pulling on a rope (without breaking it), save that now you have heat dissipation from 2 people and tension at play. You have lots of thermodynamic work going on, but no mechanical work at all (at least, until the rope breaks).

[AgentZero]

Four pages of debate on the principles of physics before Fyron shows up. I was starting to get worried there. But now everything makes a lot more sense and I think I might have learned something too, so the wait was worth it.

Now on to more important matters. Why does my beard smell funny after I wash it? It has the same smell regardless of what I wash it with.

[Raapys]

Its gravitational potential energy. If the object falls down into any gravitational well, that turns back into kinertic energy.

So what's really being said is that graivty doesn't create or destroy energy, because it was always 'potentially' there? I.e., potential energy is being treated as existing energy.

Thanks alot for the detailed work explanation Fyron.

[Renegade 13]

AgentZero said:
Now on to more important matters. Why does my beard smell funny after I wash it? It has the same smell regardless of what I wash it with.

You must not be getting all the accumulated food particles out of it!

[AngleWyrm]

AgentZero said:
Now on to more important matters. Why does my beard smell funny after I wash it? It has the same smell regardless of what I wash it with.

The Work performed in washing it was stored as potential energy in the gravitational field. So when it came out as kinetic energy, it had picked up some field odors.

[AgentZero]

AngleWyrm said:
The Work performed in washing it was stored as potential energy in the gravitational field. So when it came out as kinetic energy, it had picked up some field odors.

Field odours! Magnificent! Now all we need is some sort of field odour nulification device to prevent post-shower smelliness. I'd pay a pretty penny for such a device, and I'm sure my brothers in fur would too.

[AngleWyrm]

Oh I like pretty pennies! New technological marvel:
The Covariantly Layered Orthagonally Teathered Hyper Energized Stored Potential Induced Nullifier

[Suicide Junkie]

It sounds like implying some wierd things there Raapys.

You do recognize that a spring and a bullet have a fixed amount of potential energy (which are commonly converted into kinetic energy and boing noises, and light, heat and kinetic energy respectively)
Same deal with separated objects in a gravitational field.
Same deal with magnets and electric charges.