90 lines
3.1 KiB
Markdown
90 lines
3.1 KiB
Markdown
# SL Physics
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The course code for this page is **SPH3U7**.
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## 1.1 - Measurements in physics
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### Fundamental units
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Every other SI unit is derived from fundamental units. Memorise these!
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| Quantity type | Unit | Symbol |
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| --- | --- | --- |
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| Time | Second | s |
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| Distance | Metre | m |
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| Mass | Kilogram | kg |
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| Electric current | Ampere | A |
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| Temperature | Kelvin | K |
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| Amount of substance | Mole | mol |
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| Luminous intensity | Candela | cd |
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### Metric prefixes
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Every SI unit can be expanded with metric prefixes.
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!!! example
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milli + metre = millimetre ($10^{-3}) m
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| Prefix | Abbreviation | Value | Inverse ($10^{-n}$) abbreviation | Inverse prefix |
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| --- | --- | --- | --- | --- |
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| deca- | da | $10^1$ | d | deci- |
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| hecto- | h | $10^2$ | c | centi- |
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| kilo- | k | $10^3$ | m | milli- |
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| mega- | M | $10^6$ | µ | micro- |
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| giga- | G | $10^9$ | n | nano- |
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| tera- | T | $10^{12}$ | p | pico- |
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| peta- | P | $10^{15}$ | f | femto- |
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| exa- | E | $10^{18}$ | a | atto- |
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### Significant figures
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- The leftmost non-zero digit is the **most significant digit**.
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- If there is no decimal point, the rightmost non-zero digit is the **least significant digit**.
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- Otherwise, the right-most digit (including zeroes) is the least significant digit.
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- All digits between the most and least significant digits are significant.
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- Pure (discrete) numbers are unitless and have infinite significant figures.
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!!! example
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In $123000$, there are 3 significant digits.<br>
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In $0.1230$, there are 4 significant digits.
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- When adding or subtracting significant figures, the answer has the **same number of decimals** as the number with the lowest number of decimal points.
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- When multiplying or dividing significant figures, the answer has the **same number of significant figures** as the number with the lowest number of significant figures.
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- Values of a calculated result can be **no more precise** than the least precise value used.
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!!! example
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$$1.25 + 1.20 = 2.45$$
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$$1.24 + 1.2 = 2.4$$
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!!! warning
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When rounding an answer with significant figures, if the **least significant figure** is $5$, round up only if the **second-least** significant figure is odd.
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$$1.25 + 1.2 = 2.4$$
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$$1.35 + 1.2 = 2.6$$
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### Scientific notation
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Scientific notation is written in the form of $m×10^{n}$, where $1 \leq m < 10, n \in \mathbb{Z}$. All digits before the multiplication sign in scientific notation are significant.<br>
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!!! example
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The speed of light is 300 000 000 ms<sup>-1</sup>, or $3×10^8$ ms<sup>-1</sup>.
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### Orders of magnitude
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The order of magnitude of a number can be found by converting it to scientific notation and taking its power of 10.
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!!! example
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- The order of magnitude of 212000, or $2.12×10^{5}$, is 5.
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- The order of magnitude of 0.212, or $2.12×10^{-1}$, is -1.
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## 1.2 - Uncertainties and errors
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## 1.3 - Vectors and scalars
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## Resources
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- [IB SL Physics Syllabus](/resources/g11/ib-physics-syllabus.pdf)
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- [Dealing with Uncertainties](/resources/g11/physics-uncertainties.pdf)
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- [Linearising Data](/resources/g11/linearising-data.pdf)
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