Physics Various examples of physical phenomena Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy.[8] Over the last two millennia, physics was a part of natural philosophy along with chemistry, certain branches of mathematics, and biology, but during the Scientific Revolution in the 17th century, the natural sciences emerged as unique research programs in their own right.[b] Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. Physics also makes significant contributions through advances in new technologies that arise from theoretical breakthroughs. History Ancient astronomy Astronomy is the oldest of the natural sciences. Natural philosophy Classical physics Physics became a separate science when early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics.[15] Philosophy
Suprathreshold stochastic resonance Suprathreshold Stochastic Resonance (SSR) is a variant of stochastic resonance (SR) that occurs for a specific set of conditions that are somewhat different from those of stochastic resonance. Like stochastic resonance, suprathreshold stochastic resonance describes the observation of noise enhanced behaviour in signal processing systems. Unlike conventional stochastic resonance, suprathreshold stochastic resonance does not disappear when the signal is no longer "subthreshold." Introduction Suprathreshold stochastic resonance was first demonstrated in arrays of identical threshold devices in 2000. Most importantly, stochastic resonance occurs regardless of whether the input signal is entirely subthreshold or not, and indeed the suprathreshold stochastic resonance peak in performance is maximized when the threshold levels are set equal to the signal mean, and diminishes otherwise. Figure 1 shows a simple example that satisfies these properties. Key theoretical results Auditory nerve See also
Open Text Book Free Downloads | Mechanics of Materials The material currently available for download is all intended for intermediate mechanics of materials. The sample syllabus in pdf file shows the syllabus in readable format. The syllabus in text for is uploading it into a spreadsheet or a word processor. This online material has been created for educational use by faculty and students. SyllabusSyllabus as PDF file Syllabus as TXT file SlidesChapter 1: Stress and Strain Chapter 2: Material DescriptionChapter 3: Basic Structural MembersChapter 4: Composite Structural MembersChapter 5: Inelastic Structural BehaviorChapter 6: Thin-Walled Structural Members Chapter 7: Energy MethodsChapter 8: Elasticity and the Mechanics of Materials Sample Exams: If images appear distorted, download the file rather than view it in the browser
Motion Mountain - The Free Physics Textbook for Dowload schoolphysics The WWW Virtual Library Videos | Mechanics of Materials I recorded the short videos below to help with questions that I imagined might arise for users like yourself. If you would prefer to view the written version, here is a transcript of the questions and answers in the videos. I hope you find the videos and transcripts useful. In the first video, I introduce myself and describe why I am creating this website. Next, I provide a short explanation of where mechanics of materials fits into the engineering world: Here I discuss the relevance of mechanics of materials to everyday life: Then I share the philosophy that underlies my work in writing text books: I explain the differences between the Introduction, Intermediate, and Advanced. Finally, I outline the timeline for the development of this site.
Scala di Mohs Da Wikipedia, l'enciclopedia libera. Un blocco di talco. Un diamante tagliato a brillante.[1] La scala di Mohs è un criterio empirico per la valutazione della durezza dei materiali. Il primo minerale della serie è il talco, l'ultimo il diamante. Per determinare la durezza di un campione non si fa altro che provare quali elementi della scala riesce a scalfire e da quali viene scalfito. Esiste anche una scala assoluta di durezza, la scala di Rosiwal, che fornisce il valore reale della durezza, ottenuto con prove di laboratorio usando uno sclerometro. La scala di Mohs nella pratica[modifica | modifica sorgente] Minerali di riferimento della scala di Mohs[2] Per fare alcuni esempi, in questa scala la durezza di un'unghia è di 2,2, della punta di un coltello di acciaio da 5,1 a 5,5, del vetro da finestre da 5,6 a 6,5, di una lima da ferro di circa 6,5, della porcellana da 6 a 7; alcuni tipi di ceramica, tra cui il grès porcellanato, possono raggiungere la durezza 8.
Physics | Main Richard Feynman is a hero of mine. If you like physics, you should get to know his work. You can find a list of Feynman resources here. A note on how I teach mechanics The kinematic equations are commonly presented and used in the mechanics portion of introductory physics courses. The problem I have with introducing them too early is that they lead to a rote approach to problem solving that in the end won't serve you well in your study of physics. Instead, I strongly suggest that you solve every problem as if you were "re-inventing the wheel" every time. Think about problems in the simplest terms: What is happening physically? You'll find that in no time, as you repeat similar kinds of problems and as you notice patterns, that you'll start to take shortcuts. All of the problems solved in problem sets and examples in this section are solved using this approach.
Wikibooks Mechanics of Materials | Expanding Educational Horizons, LLC Orizzonte degli eventi Da Wikipedia, l'enciclopedia libera. In rosso l'orizzonte degli eventi, in azzurro/grigio la ergosfera Un orizzonte degli eventi è, nell'accezione più diffusa, un concetto collegato ai buchi neri, una previsione della relatività generale. È definita come la superficie limite oltre la quale nessun evento può influenzare un osservatore esterno. Secondo la teoria della relatività, lo spazio ed il tempo formano un unico complesso con quattro dimensioni reali (detto spazio-tempo), il quale è deformato dalla presenza di massa (o di energia). Nel caso di un buco nero di Schwarzschild, l'orizzonte degli eventi si crea nel momento in cui, in un corpo autogravitante, la "materia" (concetto utilizzato qui per identificare insieme la massa e l'energia, che secondo la relatività generale sono la stessa cosa) è così concentrata che la velocità di fuga dovrebbe essere pari o addirittura superiore a quella della luce. dove M è la Massa, G la costante di gravitazione universale e c la velocità della luce.
Einstein for Everyone Title page, Preface and Table of Contents for Einstein for Everyone Introduction: the Questions Special Relativity Special Relativity: the Principles Special Relativity: Clocks and Rods Special Relativity: Adding Velocities Special Relativity: the Relativity of Simultaneity Is Special Relativity Paradoxical? E=mc2 Origins of Special Relativity Einstein's Pathway to Special Relativity Spacetime Spacetime Spacetime and the Relativity of Simultaneity Spacetime, Tachyons, Twins and Clocks What is a four dimensional space like? Philosophical Significance of the Special Theory of Relativity. Skeptical Morals Morals About Theory and Evidence Morals About Time The Conventionality of Simultaneity Non-Euclidean Geometry Euclidean Geometry: The First Great Science Euclid's Fifth Postulate Non-Euclidean Geometry: A Sample Construction Non-Euclidean Geometry and Curved Spaces Spaces of Constant Curvature Spaces of Variable Curvature General Relativity General Relativity Gravity Near a Massive Body Cosmology and Black Holes