Metric Units.Pdf
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Metric Units: (adapted from http://en.wikipedia.org/wiki/Metric_system ) CGS centimeter gram second system MKS meter kilogram second system Variants of the metric system Quantity CGS MKS length (l) centimeter (cm) meter (m) Meter = 100 centimeters mass(m) gram (g) kilogram (kg) The kilogram (SI symbol: kg), also known as the kilo, is the base unit of mass in the International time (t) second (s) second System of Units. (kilogram = 1000 gram(g) ) velocity(v) cm/s m/s acceleration (a) cm/s² m/s² 1 dyne = 1 g·cm/s² = 10−5 kg·m/s² = 10−5 Newton force (F) dyne (dyn) newton (N) 1Newton = 1 kg·m/s2 pressure (p) barye (Ba) pascal (Pa) 1 Ba = 0.1 Pascal = 0.1 Newton/m2 = 1 g·cm-1s-2 2 2 −7 energy (W) erg (erg) joule (J) 1 erg = g·cm /s = 10 joules (1 erg = 1 dyne cm = 1 g·cm2/s2) 1 joule = 107 erg power (P) erg/s watt (W) 1 watt = one joule per second (power measures viscosity (µ) poise (p) Pa·s the rate of energy conversion) 1 poise = 1 g·cm-1·s-1 (1 Pascal·s = 1Pa·s = 1 -1 -1 kg·m ·s (the extent to which a fluid resists a tendency to flow) The International System of Units (System international units or SI) is the current international standard metric system and the system most widely used around the world. Mass can be defined as a quantitative measure of an object's resistance to the change of its speed. In addition to this, gravitational mass can be described as a measure of magnitude of the gravitational force which is 1. exerted by an object (active gravitational mass), or 2. experienced by an object (passive gravitational force) Whenever the mass, m, appears in our formulas, we substitute the ratio of the convenient force-acceleration pair (w/g), and measure the mass in lbs. per ft./sec.2 or in grams per cm./sec. Recall that weight is a force, so the metric unit of weight (or any other force - such as that of a stretched spring, or a bat striking a ball, or a locomotive pulling a train) is the dyne or Newton. .