Applications and Skills
Using SI units in the correct format for all required measurements, final answers to calculations and presentation of raw and processed data
Using scientific notation and metric multipliers
Quoting and comparing ratios, values and approximations to the
nearest order of magnitude
Estimating quantities to an appropriate number of significant figures

Understandings
Fundamental and derived SI units
Scientific notation and metric multipliers
Significant figures
Orders of magnitude
Estimation

The SI System

The International System of Units (SI, abbreviated from the French Système International d’unités) is the modern form of the metric system, and is the most widely used system of measurement. It is the world standard system of units.
Physics is the study of forces and matter’s reaction to it. To do so, physicists deal with physical quantities.
A physical quantity is anything measurable such as mass, length, time, etc.
Fundamental quantities are the most basic ones: everything can be expressed in terms of them. Other quantities are called derived quantities.

Example of a derived quantity:

$$ \text{The density equation} \to \rho = \frac{m}{v} $$

The units of the fundamental quantities are called fundamental unit. There are seven of them; and they constitute the SI system.

A derived quantity has a unit (derived unit) which is a combo of fundamental units.

Examples:

<aside> 💥 Sometimes, it is still valid to use derived units instead of fundamental units if it is too “heavy”. Example: pressure

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