Any measurements in physics only make sense if they are understood within a system of units. The British system is commonly used in America, while the metric system is commonly used in most other regions of the world. There are two main systems of metric measurement. The first is known as the SI system or MKS system, so called because it is based on the meter (m), kilogram (kg), and second (s). The other metric system is referred to as the CGS system and is based on the metric units of the centimeter (cm), gram (g), and second (s). Whatever the unit system, however, the actual dimensions measured are constant.
