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HNQ
12:32 AM
4
Q: Relative efficiency of airplanes and helicopters, why is this argument wrong?

TheEnvironmentalistI'm trying to better understand why helicopters are less fuel efficient per unit distance than airplanes. One argument I keep seeing in other questions on the topic is that helicopters actively contribute energy toward both horizontal translation and maintaining vertical position, whereas airplan...

 
HNQ
12:57 AM
5
Q: Why is the Pauli's exclusion principle not violated in the two neutron beams interference experiments?

Markoul11It is my understanding so far that in this kind of experiments like the one measuring the 4π (i.e. 720° Dirac Belt trick) rotation characteristic of 1/2 spin fermions like neutrons, two neutron beams are polarized via S-G apparatus to the same quantum spin number. The two separated polarized beam...

 
HNQ
1:21 AM
2
Q: Can artificial neural networks be effective theories?

GalenWikipedia describes "effective theories" as follows. In science, an effective theory is a scientific theory which proposes to describe a certain set of observations, but explicitly without the claim or implication that the mechanism employed in the theory has a direct counterpart in the actual c...

 
 
2 hours later…
HNQ
3:51 AM
2
Q: Proof that you can't disentangle two parties if you only operate on one

FriendlyLagrangianLet $A$ and $B$ be two entangled systems. Can someone prove or sketch a proof of why you cant unentangle $A$ and $B$ by only acting on $A$ or $B$ alone? i.e. by only applying $\mathbb{I}_A\otimes U_B$, with $U_B$ unitary.

 
 
5 hours later…
HNQ
9:16 AM
4
Q: Why are potential drops concentrated at resistive elements?

P0W8J6I do not understand why potential differences in the electric field in a circuit are concentrated at resistors when the potential, to my knowledge, is purely dependent upon location in the field and the magnitude of the charges. Why is the decrease in potential concentrated at resistive elements,...

 
 
4 hours later…
HNQ
1:00 PM
3
Q: Automatic chicken waterer problems

Tim GilesI am trying to build a 5 gallon bucket style chicken waterer. My bucket has an o-ring airtight lid with pour spout and cap. I have drilled a 1/2 inch hole about an inch up from the bottom. The bucket sits in a 4 inch tall catch pan. When I put my finger on the hole and fill the bucket, then put t...

 
 
4 hours later…
HNQ
4:45 PM
1
Q: What is the cause and what is the effect in the Bernoulli effect?

Andrew SteaneThere is widespread confusion (among learners) about the Bernoulli effect, and I think a large part of this confusion is owing to muddling up cause and effect. So I am providing this question and answer to see if others find it helpful. Let's consider laminar flow (i.e. smooth flow in layers) of ...

 
 
6 hours later…
HNQ
10:34 PM
2
Q: What is the tangent vector a function of?

Egg ManI'm reading R. Wald's General Relativity. It defines a tangent vector $v$ as a function, whose domain is the collection of $C^{\infty}$ functions from a manifold $M$ to $R$, and whose range is the real numbers. It's written as $v:F\rightarrow R$. $F$ is the set of functions $f: M\rightarrow R$. S...

 

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