In the Ray Kurzweil's book How to create a mind is said that:      The mathematics of how Bernoulli's principle produces wing lift is still not yet fully settled among scientist [...]    What does this statement mean? I have always known that the Bernoulli equations were well known. There is something that I am missing?
I understand that the Bernoulli effect is a flawed explanation for the cause of lift, and does not cause much at all, but how much?   Is there any experimental data on the force caused by the Bernoulli effect? Maybe implicitly through data of the pressure difference between the top and underside of an aeroplane's wings. After that, I assume I could (crudely approximating the pressure to be acting perpendicularly to the flight direction) use $\Delta P A$ to work out the net force on the plane.    Perhaps there is another way to quantitatively analyse the extent to which the Bernoulli effect causes lift.  Edit: see  short cartoon (content similar to Mike Dunlavey's answer).
How to achieve screen tearing effect or video glitches I do not know at all what this effect is called, therefore I cannot search for the answer on the web. I am referring to the thing where the RGB color will shift individually when the camera jitters/move  So, how can I achieve this sort of effect in blender? and for future reference, what is this effect called? Can anyone identify this 90s teen-fantasy series, gems in backbone, big magic, evil king? Check if a class is derived from a generic class I have a generic class in my project with derived classes.  public class GenericClass&lt;T&gt; : GenericInterface&lt;T&gt; { }  public class Test : GenericClass&lt;SomeType&gt; { }   Is there any way to find out if a Type object is derived from GenericClass?  t.IsSubclassOf(typeof(GenericClass&lt;&gt;))   does not work. This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, navigate to the  tag. This question and answer is owned by the community! If you can improve it and make it more useful, you're welcome to edit it. I have a collection of records, like a List&lt;sObject&gt; or the Trigger.new context variable. I need to query other records that are related to these records either directly or indirectly, and I want to use the related data to make further updates. When I write a query in a loop, like for (Account a : Trigger.new) {     Account parent = [SELECT Name FROM Account WHERE Id = :a.ParentId];     // ... }  I keep hitting Salesforce query limits, and I know this is not best practice. What can I do to avoid this problem and bulkify my code? Cheap/free tool to view/convert Canon CR2 RAW format photo files on Windows? How to download, modify, build and install a Debian source package? If I want to make minor changes to the source code of a Debian package, how do I go about downloading, incrementing the package version, building the (modified) source, and installing it on my computer? Dirac's remark that inspired Feynman when formulating path integral When Feynman was trying to formulate  of quantum mechanics, he was inspired by Dirac's remark which roughly states that $e^{i\frac{S}{\hbar}}$corresponds to the transition amplitude, where $S$ is the action.   I'm wondering what was Dirac's original argument behind this statement. I will soon buy a new iPhone. If I log in with my Apple ID in my new phone could I still access my Clash of Clans village without starting from scratch? Substituting table salt or sea salt for kosher salt? The roasted chicken recipe I'm following of course calls for kosher salt, but I don't have any, and getting some is out of the question.  I have sea salt and table salt on hand.  Can I substitute one of those instead, and if so, what is the proper ratio of the kosher salt the recipe calls for to either sea salt or table salt? I have recently installed ubuntu 11.10. But when i try to install a software it tries to 'updating cache' but after a while, it stops, showing:                            Failed to download repository information                           Check your internet connection   so, now i am totally unable to install any software in my ubuntu.  Please,let me know how to solve the problem. Can you help me resolve this paradox for a geodesic orbit? Does it maximize proper time to sit still rather than orbit for 1 year? Why has Steve Nash moved to the LA Lakers in sign-and-trade deal? Congratulations to Steve Nash on his move to Lakers !  His contract with the Suns has expired so I don't understand why he moved in a sign-and-trade deal.    Why resign and move in trade? Why didn't the Lakers sign Nash without any trade? This formula provides the $n$th term in the Fibonacci Sequence, and is defined using the recurrence formula: $u_n = u_{n − 1} + u_{n − 2}$, for $n &gt; 1$,  where $u_0 = 0$ and $u_1 = 1$.   Show that     $$u_n = \frac{(1 + \sqrt{5})^n - (1 - \sqrt{5})^n}{2^n \sqrt{5}}.$$    Please help me with its proof. Thank you. How many $4$ digit even numbers have all $4$ digits distinct ?   This question has been asked if we replace even with positive.   I was solving this Problem like: For first position $1-9$ (No $0$) for next $0-9$ (leaving out the digit which has been choose) for next $0-9$ (leaving out $2$ digits), but on last digit I get stuck. From what I should choose. Will it be $0, 2, 4, 6, 8$, because number needs to be even? How should I solve it? What does "--" (double-dash) mean? I have seen -- used in the compgen command.  For example:  compgen -W "foo bar baz" -- b   What is the meaning of the -- in there? How does ACF & PACF identify the order of MA and AR terms? It's been more than 2 years that I am working on different time series. I have read on many articles that ACF is used to identify order of MA term, and PACF for AR. There is a thumb rule that for MA, the lag where ACF shuts off suddenly is the order of MA and similarly for PACF and AR.   Here is  I followed from PennState Eberly College of Science.   My Question is why is it so? For me even ACF can give AR term. I need explanation of thumb rule mentioned above. I am not able to understand thumb rule intuitively/mathematically that why -  Identification of an AR model is often best done with the PACF. Identification of an MA model is often best done with the ACF rather than the PACF  Please note:- I don't need how but "WHY". :) Why are true and false so large? How to boot WUBI installed Ubuntu within Windows 8? Two "offtopic" flag reasons I am being driven crazy by the fact that my media keys aren't working for iTunes. Such a pain! How can I fix this? I've tried the whole Chrome Extensions thing, that being I deleted all my extensions. Still, nothing has fixed this. Thanks to all who reply!