The metric system has units in powers of ten for ease in computations

The metric system has units in powers of ten for ease in computations

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The metric system has units in powers of ten for ease in computations, with prefixes nano = 10 -9 = 1/1,000,000,000, as in nanometers (nm). The speed of light is 1 foot per nanosecond. micro = 10 -6 = 1/1,000,000, abbreviated µ. A micrometer is often called simply a micron. milli = 10 -3 = 1/1,000. Used everywhere: millimeters (mm), milligrams (mg), milliseconds. centi = 10 -2 = 1/100. Mostly important for centimeters (cm). 1 inch is exactly 2.54 cm. kilo = 10 3 = 1,000. One kilometer (km) = 5/8 mile. Time in hours, years, not kiloseconds. mega = 10 6 = 1,000,000. Mostly used for MB, megabytes. Megameters and Megagrams never caught on. Angular Measure is used to measure arc lengths in the sky. A circle has 360° (degress). The distance between the pointers of the Big Dipper is about 5°. The angle is formed by drawing a line from the star to your eye to the other star,
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Unformatted text preview: but the best way to think of it is like a flat ruler placed on the sky. One degree = 60' (minutes). The sun's or moon's diameter is about 30', or 1/2. One minute = 60" (seconds). One second is the smallest separation visible in most telescopes. Angular Measure is also used to measure arc lengths on the spherical earth. 1 is the north-south length of the corner missing from the otherwise rectangular shape of Utah. 1' of latitude is one nautical mile (a little more than a usual mile). 1" of latitude is almost exactly 100 feet. Note that angles of longitude are less than latitude because longitudinal lines get closer together as one approaches the poles. For example, Utah is 5 high and 5 wide, but it doesn't look square....
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