swansont

In what way?

Seems to be ionic wind. Pretty useless in space. I've never seen any demo that shows it working enclosed in a vacuum. Pretty useless if it generates a few grams*g of thrust and can't lift the 5 kg power supply, not to mention the fuel source you'd need.

The physics definition of work is not the same as the lay definition of work. Let's say the glass of water was on a table' date=' in an elevator. Where's the heat flow? Work is the integral of Force (dot) displacement Once you stop moving, there is no more displacement, so no more work is done. No change in PE.

No, if you square it you get a cross-term. I erred in my post. Serves me right, trying to watch the game and post at the same time.

Egads, yes. A brainfart on my part.

No, I never said the energy "flowed into the water." The energy is is the water/earth system. Discussing the scenario where the water "just appears" is nonsensical; you are already violating energy conservation. You can't use it as a counter-argument to energy conservation! How does the energy appear as heat? Are you implying that if I carry a glass of water in an elevator that its temperature will increase?

How are you writing the law? If you write it as (T1/T2)2 = (a1/a2)3 then you use the same units for numerator and denominator. You can always convert to other units.

It sounds like he's saying that if you assume the final entropy is zero (or whatever we started with), then it has to decrease, which is assuming the answer.

Right. But that's just the nature of optics. It's a common misconception that lasers produce parallel light.

But .511 is close enough for government work.

p is momentum. The momentum of a photon is E/c, and that has been verified many, many times by virtue of the fact that laser cooling works.

But in raising the water to some height, you have to do work. And when the water falls, it can do work. That's why we need potential energy.

For spin1/2 atoms, one way would be to confine them in a potential well, and cool them into the ground state. Since they are fermions, they would have to be of opposite spin orientation.

511 keV/c2

Yes' date=' the concept is derived from work and energy. That you are unfamilar with the math does not make potential energy nonexistant. But here's the math: dW= F (dot) dx Integrate the equation. If F is constant, W = F(dot)s cos(theta) for gravity, F = mg If you do work on a system in the presence of a field force, the energy has to go [i']somewhere[/i]

Why do you think it doesn't?

g=32 ft/s2 Nobody uses English units Three errors in one sentence. That's pretty efficient.

(emphasis added) Source, please. Any unsubstantiated link between entropy and consciousness is bunk, until demonstrated otherwise.

Actually E = mc2 + p2c2 (and Planck's constant is h, not H.)

When physicists discuss mass, they mean rest mass. What you're using is "relativistic mass" which isn't used because it confuses the issue. But it's used a lot by some who know only a little physics. They are largely the same ones who don't know the difference between speed and velocity, who think that you can't accelerate unless you change your speed, and use weight when they mean mass. Photons are massless.

You can't. Spin is inherent to the system. All you can do is change the orientation. That will depend on, and be measured in reference to, an external magnetic field. But the magnitude of the spin is fixed.

An object can have energy without being energy.