Corwin

Then what, pray tell is it exactly Einstein? Matter? Thought? Pink and purple elephants?

Kinetic force is energy. Energy HAS to go somewhere. Under ordinary circumstances the amount of mass we're talking about isn't all that much... it doesn't involve all that much energy. (A 2kilo rock falling from a height of about 2 meters doesn't make an incredible amount of heat...) Take that same 2kilo rock and drop it from the moon? Enough heat and force to level entire cities. In the case of the weight of the earth that energy is even greater, and is contained within the rock that absorbs it.

Of course some of this energy will be radiated off... but not all of it.

Corwin

Ummmm.... tron?


EXACTLY WHAT THE HELL DO YOU THINK IS HAPPENING HERE THEN?!?!?!?!?!?!?!?!?!?!?!?!?!?!?

bluefugue

Finally he takes off the sunglasses.

Corwin

I slipped.

tronvillain

Corwin:
It's force per unit area. That's it.

I think you are very confused, since force is by definition not energy. A two kilogram rock falling from a height of two metres will hit with about 39.2 joules of kinetic energy, but support it at that height and it will simply retain those 39.2 joules as potential energy. If it is sitting on a table, it will press down on that table with a force of 19.6 newtons, but that does not result in the loss of any energy.

It's just potential energy, and is analagous to the rock sitting on the table, not the rock falling.

Deimos

This is the same confusion that free energy folks suffer from when they hold up the 'fridge magnet' analogy to 'prove' that permanent magnets can do mechanical work by simply pressing themselves against a metallic surface.

As mentioned by tronvillain, force and energy are NOT equivalent. In order for energy to be converted the force must undergo a displacement. The only way for the pressure forces in the earth to contribute to its present heat flux would be for the earth to shrink in diameter.

Corwin

Since when is potential energy not energy?

It's energy regardless of whether humans are using it for anything or not.

And how do you come up with the 39 joules figure? Ah... F=MA. An expression of energy. Potential or kinetic.... doesn't matter.

tronvillain

Corwin:
It's potential energy. Not only are humans not using it for anything, it's not doing anything. In the case of the Earth, it is not heating the Earth's core.

The equation F=ma is not an expression of energy, so obviously the 39.2 joules figure was not obtained from it. Energy is measured in joules, while force is measure in newtons - the two are simply not the same.

PE = mgh = (2)(9.8)(2) = 39.2 J

KE = (mv^2)/2 = [(2)(6.26)^2]/2 = 39.2 J

F = ma = (2)(9.8) = 19.6 N

[ March 07, 2002: Message edited by: tronvillain ]</p>

Corwin

And what is a joule?

Oh yes.... one newton/meter.

BOTH are energy.

Your two kilogram rock? Call it potential energy if you want to, but it's still exerting force/energy on whatever it's hanging from. If it's sitting on a table? It's exerting downward force.... these are energy.

Friar Bellows

No, it's newtons * meters (newtons multiplied by meters, not newtons divided by meters, as you have written).

Oh dear. You really don't have a clue about this kind of thing. I guess someone who can't tell the difference between force, pressure and energy is quite happy to believe that pressure keeps the earth's interior hot. Pressure is anything, according to Corwin, so I guess Corwin's pressure really is the cause! All hail Corwin's pressure:

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