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 States, a "hundredweight" (abbreviated as cwt) is a unit of weight or mass used in various industries, especially in agriculture and commerce. The hundredweight is equivalent to 100 pounds (lbs). It is often used to express weights or quantities of goods, particularly in contexts like the sale of agricultural products, grains, and some industrial materials.
1 hundredweight (US) = 100 pounds (lbs)
Hundredweights are commonly used in trade and commerce, especially for bulk items where the use of pounds or tons may not be as convenient. It provides a middle-ground unit for measuring weight between the pound and the ton. When you see prices or quantities listed in hundredweights in the United States, it means that they are referring to units of 100 pounds each.