SI Units and Worked Examples [antikvár]

Preface This booklet is primarily for those studying the science of mechanical engineering. Its purpose is to present the coherent Systeme International d'Unités (the SI) and help students develop a facility for coping con- fidently with units and quantitative work generally. The advantages and ease of application of the SI is demonstrated in a selection of worked examples from mechanical engineering involving mechanics of materials, machines, fluids and applied thermodynamics. Letter-symbols for physical quantities, and the abbreviations (or unit-symbols) for units are in line with the recent recommendations of the British Standards Institution (BSI) and the international standards organisations namely, the Conférence Général des Poids et Mesures (CGPM) and the International Standards Organisation (ISO). Attention is given to the development and use of physical and numerical (including empirical) formulae in which letter-symbols represent physical quantities as specified by numbers multiplied by units and numbers only, respectively. Although the former are by far the most important in that they are universal and independent of particular units or systems of units, students and engineers encounter and use both, and it is essential that they be in no doubt as to how all formulae are derived before they are used. Also, students of science and technology should not only be 'dimension-conscious', but have a sure method of checking and dealing with units and of overcoming any difficulties with them in calculations. The majority of the examples chosen are relatively easy, which students may first try to solve for themselves, for the booklet is primarily intended for students who are in the early stages of their studies. A.C.W.