PHY 101 Lecture Notes - Lecture 1: Luminous Intensity, Decimal Mark, Electric Current
20 Jan 2018
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Formulas do not have to be memorized, but must know powers of 10. Example: 6. 41 x 10^-8 s=64. 1 x 10^-9 s=64. 1 nanoseconds (ns) Use multiples of 3 (3,6,9, etc. ) to use engineering shorthand. Engineering shorthand: prefixes like nano, mega, milli, etc . Do not round until the very end! 5 fingers on a hand: infinite significant figures because it is not. 5 cm length: 1 significant figure because it is a measured quantity. Example: convert 20m to ft: 20m/1 x 1ft/. 305m =65. 57m (but not correct significant figures, round answer to only 1 significant figure because 20m has only 1 significant figure, answer=70m. Fallacy of fake precision: making a claim that uses mathematical precision without any actual data. Example: you ignore me 90% of the time! ; we only use 10% of our brain power . How to counter it?- demand data or cite a study. Make sure to keep track of units. Use correct units for each unit of measurement.
