Mechanics and Thermodynamics

Abstract

The present textbook represents the first part of a four-volume series on experimental Physics. It covers the field ofMechanics and Thermodynamics. One of its goal is to illustrate, that the explanation of our world and of all natural processes by Physics is always the description of models of our world, which are formulated by theory and proved by experiments. The continuous improvement of these models leads to a more detailled understanding of our world and of the processes that proceed in it. The representation of this textbook starts with an introductory chapter giving a brief survey of the history and development of Physics and its present relevance for other sciences and for technology. Since experimental Physics is based on measuring techniques and quantitative results, a section discusses basic units, techniques for their measurements and the accuracy and possible errors of measurements. In all further chapters the description of the real world by successively refined models is outlined. It begins with the model of a point mass, its motion under the action of forces and its limitations. Since the description of moving masses requires a coordinate system, the transformation of results obtained in one system to another system moving against the first one is described. This leads to the theory of special relativity, which is discussed in Chap. 3. The next chapter upgrades the model of point masses to spatially extended rigid bodies, where the spatial extension of a body cannot be ignored but influences the results. Then the deformation of bodies under the influence of forces is discussed and phenomena caused by this deformation are explained. The existence of different phases (solid, liquid and gaseous) and their relation with external influences such as temperature and pressure, are discussed. The properties of gases and liquids at rest and the effects caused by streaming gases and liquids are outlined in Chap. 7 and 8. Many insights in natural phenomena, in particular in the area of atomic and molecular physics could only be explored after sufficiently good vacua could be realized. Therefore Chap. 9 discusses briefly the most important facts of vacuum physics, such as the realization and measurement of evacuated volumina. Thermodynamics governs important aspects of our life. Therefore an extended chapter about definitions and measuring techniques for temperatures, heat energy and phase transitions should emphazise the importance of thermodynamics. The three principle laws ot thermodynamics and their relevanve for energy transformation and dissipation are discussed. Chapter 11 deals with oscillations and waves, a subject which is closely related to acoustics and optics. While all foregoing chapters discuss classical physics which had been developed centuries ago, Chap. 12 covers a modern subject, namely nonlinear phenomena and chaos theory. It should give a feeling for the fact, that most phenomena in classical physics can be described only approximately by linear equations. A closer inspection shows that the accurate description demands nonlinear equations with surprising solutions. A description of phenomena in physics requires someminimum mathematical knowledge. Therefore a brief survey about vector algebra and vector analysis, about complex numbers and different coordinate systems is provided in the last chapter. A real understanding of the subjects covered in this textbook can be checked by solving problems, which are given at the end of each chapter. A sketch of the solutions can be found at the end of the book. For further studies and a deeper insight into special subjects some selected literature is given at the end of each chapter.