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--- preparation_properties_proportions [2021/08/28 21:30]
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+++ preparation_properties_proportions [2022/04/22 21:19]
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 ====== 1. Preparation, Properties, Proportions ======
+===== 1.1 Physical quantities =====
+<callout>
+=== Learning Objectives ===
+By the end of this section, you will be able to:
+  - know the basic physical quantities and the associated SI units.
+  - know the most important prefixes. You can assign a power of ten to the respective abbreviation (G, M, k, d, c, m, µ, n).
+  - use numerical values and units given in an existing quantity equation. From this you should be able to calculate the correct result with a calculator.
+  - assign the Greek letters.
+  - always calculate with numerical value and unit.
+  - know that a related quantity equation is dimensionless!
+</callout>
+<callout>
+The KIT bridging course offers a similar introduction to [[https://lx3.mint-kolleg.kit.edu/onlinekursphysik/html/1.1.2/modstart.html|physical variables]]
+</callout>
+==== Basic sizes ====
+<WRAP>
+Brief presentation of the SI units
+{{youtube> Fq0J-V4PUoc}}
+<tabcaption tab01 | SI units>
+^ Base size ^ name ^ unit symbol ^ definition ^
+| Time | Second | s | Oscillation of a $ Cä $ atom |
+| Length | Meter | m | about s and the speed of light |
+| Amperage | Ampere | A | via s and elementary charge |
+| Mass | Kilograms | kg | still over kg prototype |
+| Temperature | Kelvin | K | over triple point of water |
+| Amount of substance | Mole | mol | over the number of the $ ^ {12} C $ nuclide |
+| Light intensity | Candela | cd | over specified radiation intensity |
+</tabcaption>
+</WRAP>
+  * For the practical application of physical laws of nature, ** physical quantities ** are put into mathematical relationships.
+  * There are basic sizes based on the SI system of units (French for Système International d'Unités), see below
+  * In order to determine the basic parameters quantitatively (quantum = Latin "how big"), ** physical units ** are defined, e.g. $ meter $ for the length
+  * In electrical engineering, the first three basic variables (see <tabref tab01>) are particularly important. \\ the mass is important for the representation of energy and power.
+  * Each physical quantity is indicated by a product of ** numerical value ** and ** unit **: \\ e.g. $ I = 2 A $
+    * This is the short form of $ I = 2 \ cdot 1A $
+    * $ I $ is the physical quantity, here: electrical current strength
+    * $ \ {I \} = 2 $ is the numerical value
+    * $ [I] = 1 A $ is the (measurement) unit, here: ampere
+~~PAGEBREAK~~ ~~CLEARFIX~~
+==== derived quantities, SI units and prefixes ====
+<WRAP>
+<WRAP group> <WRAP half column>
+<tabcaption tab02 | Prefixes I>
+^ Prefix ^ Prefix characters ^ Meaning ^
+| Yotta | Y | $ 10 ^ {24} $ |
+| Zetta | Z | $ 10 ^ {21} $ |
+| Exa | E | $ 10 ^ {18} $ |
+| Peta | P | $ 10 ^ {15} $ |
+| Tera | T | $ 10 ^ {12} $ |
+| Giga | G | $ 10 ^ {9} $ |
+| Mega | M | $ 10 ^ {6} $ |
+| Kilos | k | $ 10 ^ {3} $ |
+| Hecto | h | $ 10 ^ {2} $ |
+| Deka | de | $ 10 ^ {1} $ |
+</tabcaption>
+</WRAP> <WRAP half column>
+<tabcaption tab02 | Prefixes II>
+^ Prefix ^ Prefix characters ^ Meaning ^
+| Deci | d | $ 10 ^ {- 1} $ |
+| Zenti | c | $ 10 ^ {- 2} $ |
+| Milli | m | $ 10 ^ {- 3} $ |
+| Micro | u, $ \ mu $ | $ 10 ^ {- 6} $ |
+| Nano | n | $ 10 ^ {- 9} $ |
+| Pico | p | $ 10 ^ {- 12} $ |
+| Femto | f | $ 10 ^ {- 15} $ |
+| Atto | a | $ 10 ^ {- 18} $ |
+| Zeppto | z | $ 10 ^ {- 21} $ |
+| Yokto | y | $ 10 ^ {- 24} $ |
+</tabcaption>
+</WRAP> </WRAP>
+</WRAP>
+  * In addition to the basic sizes, there are also derived sizes, e.g. $ 1 {{m} \ over {s}} $
+  * SI units should be preferred for calculations. These can be derived from the basic quantities ** without a numerical factor **.
+    * The pressure unit bar ($ bar $) is an SI unit
+    * BUT: The outdated pressure unit atmosphere ($ = 1.013 bar $) is ** __ not a __ ** SI unit
+  * In order not to let the numerical value become too large or too small, it is possible to replace a decimal factor with a prefix. These are listed in the <tabref tab02>.
+Example for calculating the power
+{{youtube> fwUyMBtdrvw}}
+~~PAGEBREAK~~ ~~CLEARFIX~~
+==== physical equations ====
+  * Physical equations enable physical quantities to be linked
+  * There are two types of physical equations to be distinguished:
+    * Equations of size
+    * standardized size equations (also called related size equations)
+<WRAP group> <WRAP half column>
+<callout color = "gray">
+=== Equations of quantities ===
+The vast majority of physical equations result in a physical unit that is not equal to $ 1 $.
+\\ \\