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Re: DOES ZPE NEED A DIFFERENTIAL TO WORK? (Score: 1)
by Cold_Steel on Monday, August 29, 2005 @ 05:18:14 UTC
(User Info | Send a Message) | Alright, here’s a hypothetical situation that’s getting to me. Let’s say you have a 1kg brick sitting on the ground. If I lift the brick straight up 1 meter, we say it gains some potential energy x relative to the Earth. When I let it go, it transfers all (assuming a vacuum with no friction) of that potential energy into kinetic energy and thus we hold to conservation of energy.
The problem I have, however, is with the concept of potential energy. Where does the Earth get the “energy” to pull the brick back down? No text book ever really addresses that, it just says it comes from the potential energy.
Okay, now for the hypothetical situation. Let’s say I’ve invented a teleporter that uses an infinitesimal amount of energy. Now, we have a brick sitting on the ground again, but this time, instead of lifting the brick, we’re going to use our teleporter to teleport it instantaneously up 1 meter. By teleporting it directly, there’s no path integral and thus no work is being done on the brick, so, the brick can’t be gaining any potential energy, right? So, by conservation of energy, the brick is 1 meter up off the Earth and has no more potential energy than it did sitting on the ground? Its potential energy must still be 0. So, does that mean the brick will just hang in the air? Hmm. I don’t think so. If that were the case, then the universe would have to “remember” the state of every single atom and its potential energy relative to everything. Does that make any sense? You could have two identical bricks 1 meter off the ground, but one would have a different potential energy than the other, one being x, and one being zero? If you let them both go, only one will fall to the ground?
No, instead, I think that if you teleport that brick up 1 meter, that brick will fall straight back down just like a brick lifted 1 meter. Gravity is a force, not an energy supplier. Gravity will act between any two masses. It doesn’t care about conservation of energy. So, if that brick is teleported up at a cost of essentially 0 joules (to the brick-Earth system at least), but gravity pulls it back down giving it a total kinetic energy of x, we’ve violated the conservation of energy.
The reason this might be is that energy isn’t a real universal thing. It’s a scientific abstraction. Forces are what matter, and forces don’t care about energy or its conservation. A 1 kg brick 1 meter of the ground will always have the same force acting on it, no matter how the brick gets there or whether or not energy was conserved.
With ZPE, we may be talking about an “energy” that exists without a differential at 0 k? Maybe. Things like the nuclear force and gravity have constant magnitude at any given point with respect to time, right? What if ZPE is a force that’s magnitude and force vector oscillate with time? I really don’t know enough about the subject, but if you had some sort of oscillating or vibrating force then you may be able to tap into without an energy differential as with gravity and other forces.
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