From 9451c38f4577c52296154f87cacdedd6e46fad78 Mon Sep 17 00:00:00 2001
From: eggy <eggyrules@gmail.com>
Date: Sun, 20 Sep 2020 15:18:31 -0400
Subject: [PATCH] phys: add topic 1 notes

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-# Grade 11 SL Physics
+# SL Physics
 
 The course code for this page is **SPH3U7**.
 
+## 1.1 - Measurements in physics
+
+### Fundamental units
+
+Every other SI unit is derived from fundamental units. Memorise these!
+
+| Quantity type | Unit | Symbol |
+| --- | --- | --- |
+| Time | Second | s |
+| Distance | Metre | m |
+| Mass | Kilogram | kg |
+| Electric current | Ampere | A |
+| Temperature | Kelvin | K |
+| Amount of substance | Mole | mol |
+| Luminous intensity | Candela | cd |
+
+### Metric prefixes
+
+Every SI unit can be expanded with metric prefixes.
+
+!!! example
+    milli + metre = millimetre ($10^{-3}) m
+
+| Prefix | Abbreviation | Value | Inverse ($10^{-n}$) abbreviation | Inverse prefix |
+| --- | --- | --- | --- | --- |
+| deca- | da | $10^1$ | d | deci- |
+| hecto- | h | $10^2$ | c | centi- |
+| kilo- | k | $10^3$ | m | milli- |
+| mega- | M | $10^6$ | µ | micro- |
+| giga- | G | $10^9$ | n | nano- |
+| tera- | T | $10^{12}$ | p | pico- |
+| peta- | P | $10^{15}$ | f | femto- |
+| exa- | E | $10^{18}$ | a | atto- |
+
+### Significant figures
+
+ - The leftmost non-zero digit is the **most significant digit**.
+ - If there is no decimal point, the rightmost non-zero digit is the **least significant digit**.
+	- Otherwise, the right-most digit (including zeroes) is the least significant digit.
+ - All digits between the most and least significant digits are significant.
+ - Pure (discrete) numbers are unitless and have infinite significant figures.
+
+!!! example
+    In $123000$, there are 3 significant digits.<br>
+    In $0.1230$, there are 4 significant digits.
+
+ - When adding or subtracting significant figures, the answer has the **same number of decimals** as the number with the lowest number of decimal points.
+ - 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.
+ - Values of a calculated result can be **no more precise** than the least precise value used.
+
+!!! example
+    $$1.25 + 1.20 = 2.45$$
+    $$1.24 + 1.2 = 2.4$$
+
+!!! warning
+    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.
+
+    $$1.25 + 1.2 = 2.4$$
+    $$1.35 + 1.2 = 2.6$$
+
+### Scientific notation
+
+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>
+
+!!! example
+    The speed of light is 300 000 000 ms<sup>-1</sup>, or $3×10^8$ ms<sup>-1</sup>.
+
+### Orders of magnitude
+
+The order of magnitude of a number can be found by converting it to scientific notation and taking its power of 10.
+
+!!! example
+    - The order of magnitude of 212000, or $2.12×10^{5}$, is 5.
+    - The order of magnitude of 0.212, or $2.12×10^{-1}$, is -1.
+
+## 1.2 - Uncertainties and errors
+
+
+## 1.3 - Vectors and scalars
+
 ## Resources
 
  - [IB SL Physics Syllabus](/resources/g11/ib-physics-syllabus.pdf)