TABLE OF CONTENTS Measurement is the basis of all science and engineering work, and hence, all industrial applications. Every measurement has two components: a quantity and a unit. The quantity gives a magnitude; the unit gives the type of measurement and a reference for comparison to other quantities of the same type. Together they describe how many, how much, how long, how heavy, how hard, how fast, and so on. Common units of measure include meter (m), second (sec), pound (lb), gallon (gal), calorie (cal), and combinations of these or other units.
Unit conversion tables are given in Appendix A.
The main dimensional systems of measurement are the English system and the SI or metric system.
The English system of measurement evolved over many centuries and reflects the patterns of commerce and local customs of earlier times. In the English system, units of length were based on the human body because it was easily referred to and understood. The standard unit of linear measure, the foot, was originally the length of the king s foot. The foot, in turn, was divided into 3 hands, 4 palms, 16 digits, or 12 inches. A farm field measuring 4 rods by 40 rods was an acre. Similarly, the weight of a barleycorn was called a grain. With so many units in use, and no unifying factor, the English system became a complicated measurement scheme. Eventually, fundamental units in the English...
