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Pacer. How does a guitar work? Contents First, something about sound If you put your finger gently on a loudspeaker you will feel it vibrate - if it is playing a low note loudly you can see it moving.

How does a guitar work?

When it moves forwards, it compresses the air next to it, which raises its pressure. Some of this air flows outwards, compressing the next layer of air. The disturbance in the air spreads out as a travelling sound wave. At any point in the air near the source of sound, the molecules are moving backwards and forwards, and the air pressure varies up and down by very small amounts. The strings The pitch of a vibrating string depends on four things. Strings, standing waves and harmonics. The animation shows the interaction of two waves, with equal frequency and magnitude, travelling in opposite directions: blue to the right, green to the left.

Strings, standing waves and harmonics

The red line is their sum: the red wave is what happens when the two travelling waves add together (superpose is the technical term). By stopping the animation, you can check that the red wave really is the sum of the two interacting travelling waves. The figure at right is the same diagram represented as a time sequence - time increases from top to bottom. Strong coupling of torsional and transverse waves in a bowed string. This page is an appendix for the scientific paper: Bavu, E., Smith, J. and Wolfe, J.

Strong coupling of torsional and transverse waves in a bowed string

"Torsional waves in a bowed string" (2005, Acustica, 91, 241-246). It has sound files of the translational and rotational waves, an animation of idealised Helmholtz motion in translation and a brief summary of the paper. This figure, reproduced from the paper, shows the velocity, in time and frequency domain representation, of the transverse and torsional waves in a bass E string, bowed by an experienced string player.

For comparison, the torsional wave is represented by rω, the product of the string radius and the angular velocity. Formulating Science in Terms of Possible and Impossible Tasks. David and I have been working on this together for the past three years, and we’ve been applying it to many different problems.

Formulating Science in Terms of Possible and Impossible Tasks

So far, the two completed parts of our trying out constructor theory to see whether it can solve problems are: a fundamental theory of information within physics1; and the constructor theory of life2, which applies this new theory of information to a fundamental problem that's at the boundary between physics and biology, and has to do with how certain features of living things, such as the ability to self-reproduce very accurately, are compatible with the laws of physics as we know them.

In these two cases, you can see how switching to this new mode of explanation allows one to change the perspective and address the problems in a much more effective way. These are two examples where switching to this new mode of explanation makes all the difference. Music - Brian Eno’s Reading List: 20 Essential Books for Sustaining Civilization. By Maria Popova Deconstructing a magnificent mind through his reading diet for intellectual survival.

Brian Eno’s Reading List: 20 Essential Books for Sustaining Civilization

UPDATE: The folks from the Long Now have kindly asked me to contribute to the Manual for Civilization library — here is my own reading list. There is something inescapably alluring about the reading lists of cultural icons, perhaps because in recognizing that creativity is combinatorial and fueled by networked knowledge, we intuitively long to emulate the greatness of an admired mind by replicating the bits and pieces, in this case the ideas found in beloved books, that went into constructing it. Tons of Albert Einstein Documents Are Now Online for Free. Einstein Papers Project at Caltech.

FLP Vol. I Table of Contents. The Feynman Lectures on Physics Vol. I Ch. 1: Atoms in Motion. Bill Gates Favorite Books. Park East Press Even though Gates can get a meeting with almost anyone, he can't land a sit-down with Norman Borlaug, the late biologist and humanitarian who led the "Green Revolution" — a series of innovations that kept a huge chunk of humanity from starving.

Bill Gates Favorite Books

"Although a lot of people have never heard of Borlaug, he probably saved more lives than anyone else in history," Gates says. "It's estimated that his new seed varieties saved a billion people from starvation," many of whom were in India and Pakistan. Borlaug was awarded the Nobel Peace Prize, the Presidential Medal of Freedom, and the Congressional Gold Medal for his efforts — and is one of only seven people to do so. For Gates, Borlaug is a model in getting important work done in the world. Mozambook - les ebooks de littérature - ebooks of literature. OpenClassrooms, Le Site du Zéro - Les cours les plus ouverts du Web.

Graphisme & interactivité blog par Geoffrey Dorne. World of Mathematics. If we can divide a number A by a number B, without remainder, we say that B is a factor or divisor of A, and that A is a multiple of B.

World of Mathematics

For example, 7 is a factor of 21, 4 is a factor of 20 and 60 is a multiple of 12. When thinking about number problems, it is often useful to find all the factors of a number. To do this, we should note that factors always appear in pairs. For example, 7 × 3 = 21, so 3 and 7 are a factor pair of 21. Let us write down these factor pairs, until we meet in the middle: And these are indeed all the factors of 24.

Some numbers are very special because they only have two factors: 1 and itself.


The Periodic Table of Videos - University of Nottingham. Find Your Name in the Periodic Table of the Elements. Top 10 Scientific Mnemonics. Humans.

Top 10 Scientific Mnemonics

To add up to. Sound Bottle : une bouteille qui remixe les sons aux alentours. 10 techniques de manipulation de l'opinion publique et de la société. Le Petit Érudit. HowStuffWorks "Learn how Everything Works!" La boite verte. TED: Ideas worth spreading. Net Sommaire. De la servitude moderne - le livre. « Mon optimisme est basé sur la certitude que cette civilisation va s’effondrer.

de la servitude moderne - le livre

Mon pessimisme sur tout ce qu’elle fait pour nous entraîner dans sa chute. » La servitude moderne est une servitude volontaire, consentie par la foule des esclaves qui rampent à la surface de la Terre. Ils achètent eux-mêmes toutes les marchandises qui les asservissent toujours un peu plus.


Béhémoth. Un article de Wikipédia, l'encyclopédie libre.


Béhémoth, ou B'hemot (Bəhēmôth — hébreu : בהמות), est une créature mentionnée dans le Livre de Job, 40:15-24. Il est connu en arabe comme بهيموث (Bahīmoūth) ou بهموت (Bahamūt) . Tour de Babel. Empire romain. Un article de Wikipédia, l'encyclopédie libre. Cet article traite d'une période de l'histoire de la Rome antique. Pour les territoires administrés par Rome, voir l'article Province romaine. Empire romain. Belzébuth. Un article de Wikipédia, l'encyclopédie libre. Language Exchange Community - Practice Foreign Languages.

¤ Portail des civilisations anciennes. Does Language Influence Culture? Les expressions françaises décortiquées - Accueil. Fractale. Un article de Wikipédia, l'encyclopédie libre. Ce terme était au départ un adjectif : les objets fractals (selon un pluriel formé sur l'exemple de "chantiers navals").

Les fractales sont définies de manière paradoxale, en référence aux structures gigognes dont ils constituent des cas particuliers : « Les objets fractals peuvent être envisagés comme des structures gigognes en tout point – et pas seulement en un certain nombre de points, les attracteurs de la structure gigogne classique. Spheres. Spheres [ english | español | portugués ] CALCULATRICE SCIENTIFIQUE EN LIGNE. Share Book Recommendations With Your Friends, Join Book Clubs, Answer Trivia. Ebooks libres et gratuits.

Ebooks gratuits - Télécharger des revues et magazines en pdf gratuits. Free Audio Books - Download an audio book in mp3 or iPod format today! FILMS7 VOD - VIDEOS - CLIPS - BANDES DEMOS COMEDIENNES - VIDEO A LA DEMANDE - FILMS A VOIR EN LIGNE - CINEMA D'AUTEUR. Gilles Deleuze : "une belle rencontre : Kurosawa et Dostoïevski. ... Qu’est-ce qui fait qu’un cinéaste a vraiment envie d’adapter, par exemple, un roman ? " : "Avoir une idée en cinéma, encore une fois, c’est pas la même chose qu’avoir une idée ailleurs. Et ce que je dis compte beaucoup parce que c’est une manière de poser une question qui m’intéresse : Free Audio Book - Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences by René Descartes.

Shahi - A visual dictionary. Visual Thesaurus. Hugh Laurie - Tout est sous contrôle - Livre Audio[MU] sur megaupload dvdrip.