MKSstelsel

MKS-stelsel, often called the MKS system, is a system of physical units based on meter, kilogram and second as the fundamental quantities. It emerged in the late 19th and early 20th centuries as a practical metric framework for physics and engineering, particularly in Europe. The MKS-stelsel served as a bridge between the older centimeter-gram-second (CGS) system and the modern International System of Units (SI).

In the MKS-stelsel, the metre (m), kilogram (kg) and second (s) are the base units. Derived mechanical units include the newton (N) = kg·m/s^2, the joule (J) = kg·m^2/s^2, and the watt (W) = kg·m^2/s^3. For electromagnetism, variations existed; when a consistent electrical base was needed, a related MKSA system (meter-kilogram-second-ampere) added the ampere as a base unit, forming a framework that evolved into the SI.

Historical role and transition: The MKS-stelsel was widely used in physics and engineering before and during the adoption of SI. It helped standardize measurements and facilitated calculations compared with the older CGS. The SI system, formalized in the 1950s and 1960s, expanded the base set with kelvin, mole, and candela, and incorporated the ampere as a base unit, ultimately superseding the pure MKS-stelsel.

Modern status: Today, the MKS-stelsel is primarily of historical interest. It is described in textbooks and encyclopedic entries as a predecessor to SI and is sometimes used to define the mechanical subset of SI.