Convert Kilogram to Slug

The kilogram originated during the French Revolution in the late 18th century as part of the metric system's development. Initially, it was defined as the mass of one cubic decimeter of pure water at 4°C, chosen for its universal availability and consistency. In 1799, a physical standard called the Kilogram of the Archives, a platinum cylinder, was created to represent the unit. Later, in 1889, the International Prototype of the Kilogram (IPK), a more precise platinum-iridium cylinder, was adopted as the global standard, stored in France with copies distributed worldwide.

Over time, physical changes in the IPK led to inconsistencies, prompting scientists to redefine the kilogram. In 2019, it was redefined based on the Planck constant (h), a fundamental constant of nature, linking the kilogram to unchanging physical properties rather than a physical object. This modern definition ensures long-term precision and stability for the unit of mass.

The slug was introduced in the late 19th century as part of the foot-pound-second (FPS) system, which was developed to be more consistent with the principles of mechanics, particularly Newton's second law of motion. The term "slug" was chosen because it represented a unit of mass that would help express the relationship between force, mass, and acceleration in a way that was easier to apply in engineering and scientific calculations. The slug is used primarily in the U.S. and some engineering contexts, but it is less common in everyday measurements, where the pound is typically used for mass and weight.