The kilogram (kg) is the base unit of mass in the International System of Units (SI). It is defined as the mass of the International Prototype of the Kilogram (IPK), a platinum-iridium cylinder kept at the International Bureau of Weights and Measures (BIPM) in France.
Until May 20, 2019, the kilogram was defined by the physical prototype, but as part of the redefinition of the SI units, the kilogram was redefined in terms of fundamental constants. Since that date, the kilogram is defined by fixing the numerical value of the Planck constant (h) to be exactly 6.62607015 x 10^-34 joule-seconds.
This redefinition ensures that the value of the kilogram is now based on a constant of nature rather than relying on a physical object that could potentially change over time. It allows for a more precise and stable definition of the kilogram and other SI units.
In the United Kingdom, a "quarter" is a term commonly used in the context of weight or mass, especially in agricultural and trade settings. A "quarter" in the UK refers to a quarter of a hundredweight (cwt).
In the United Kingdom:
1 quarter (UK) = 28 pounds (lbs)
So, when you see "quarter" used in the context of weight or mass in the UK, it generally means 28 pounds. This term is frequently used in the sale and trade of agricultural products and livestock, where quantities are often expressed in multiples of quarters. It's important to note that the UK quarter is different from the US quarter, which is 25 pounds.