In the United States, a "quarter" is a common informal term used to refer to a quarter of various units of measurement, such as a quarter of a dollar, a quarter of a year, or a quarter of other divisible quantities. However, when used in the context of weight or mass, a "quarter" typically refers to a quarter of a hundredweight (cwt).
Since a hundredweight (cwt) in the United States is equal to 100 pounds (lbs), a quarter of a hundredweight is equal to:
1 quarter (US) = 25 pounds (lbs)
So, when you see "quarter" used in the context of weight or mass in the United States, it generally means 25 pounds. This term is often used informally, especially in agricultural or trade contexts, to refer to a convenient fraction of weight.
The petagram (Pg) is a unit of mass in the metric system. It is equal to one quadrillion (10^15) grams. The petagram is commonly used in scientific and environmental contexts, particularly in discussions related to global carbon cycles, climate change, and large-scale ecological measurements.
To put it in perspective, one petagram is equivalent to 1,000 teragrams (Tg) or 1,000,000 gigagrams (Gg). It is a valuable unit for measuring and quantifying large quantities of materials, such as the mass of carbon stored in forests or the carbon emissions from human activities on a global scale. While not commonly used in everyday conversation, the petagram plays a crucial role in scientific research and discussions concerning the Earth's ecosystem and climate.