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Unformatted text preview: Chapt. 1 Quantities, Units, Conversions, Measurement, Significant Figures, and Uncertainties 11 2. Italian-American physicist Enrico Fermi once noted that a standard 50 minute university lecture was nearly a micro-century. NOTE: A Julian year, which is exactly 365.25 days, is exactly 3 . 15576 10 7 seconds. Actually, a convenient mnemonic is that a Julian year is 10 7 s which is too small by only 0 . 5 %. It just a coincidence that the Julian year is almost this number of seconds. More exactly a Julian year is 1 . 0045096 10 7 s. a) How long is a micro-century in minutes actually? b) What is the percentage difference between a standard lecture period and a micro-century. 001 qfull 00530 1 3 0 easy math: light travel time to Sun 3. The mean Sun-Earth distance, 1 . 496 10 13 cm, is a convenient standard unit in astronomy. (All astronomy is CGS, not MKS by the by.) This unit is called the astronomical unit. Given the speed of light is approximately 3 . 00 10 8 m / s, what is the light travel time from the Sun...
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This note was uploaded on 11/16/2011 for the course PHY 2053 taught by Professor Buchler during the Fall '06 term at University of Florida.
- Fall '06