Physics

The subset of mathematics describing relationships between mass and movement (energy) in the physical world.

Physical Units

• Meter (distance unit)
• Kilogram (force unit)
• Second (time unit)
• Liter (volume unit)

Sizes such as $1m$ (meter) or $1s$ (second) are examples of mathematical expressions using physically defined variables (to enable algebraic manipulation). The meter (example of one of the many SI-Units) is defined as the length of some rod in France (almost true).

Branches of Physics

Relativity [Classical Physics](Classical Physics.md)