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| - | ====== 1. Preparation, | ||
| - | ===== 1.1 Physical quantities ===== | ||
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| - | === Learning Objectives === | ||
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| - | 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! | ||
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| - | The KIT bridging course offers a similar introduction to [[https:// | ||
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| - | ==== Basic sizes ==== | ||
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| - | Brief presentation of the SI units | ||
| - | {{youtube> | ||
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| - | ^ 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 | | ||
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| - | * 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' | ||
| - | * 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, | ||
| - | * 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 | ||
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| - | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
| - | ==== derived quantities, SI units and prefixes ==== | ||
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| - | <WRAP group> <WRAP half column> | ||
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| - | ^ 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} $ | | ||
| - | </ | ||
| - | </ | ||
| - | < | ||
| - | ^ 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} $ | | ||
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| - | * 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>. | ||
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| - | Example for calculating the power | ||
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| - | {{youtube> | ||
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| - | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
| - | ==== physical equations ==== | ||
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| - | * 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) | ||
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| - | <WRAP group> <WRAP half column> | ||
| - | <callout color = " | ||
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| - | === Equations of quantities === | ||
| - | The vast majority of physical equations result in a physical unit that is not equal to $ 1 $. | ||
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