Units and SI prefixes

Understand the units behind the numbers: what each unit measures, how it is defined, and where it is useful.

Metre (m)length Kilogram (kg)mass Second (s)time Kelvin (K)thermodynamic temperature Newton (N)force Pascal (Pa)pressure Joule (J)energy Watt (W)power Hertz (Hz)frequency Litre (L)volume SI prefixes10⁻³⁰ → 10³⁰