Mass
A fundamental intrinsic property of matter that quantifies both the amount of substance in an object and its inertia (resistance to acceleration).
Governing formula
m = F / a
SI unit
kg
In depth
Mass is a scalar quantity that remains constant regardless of location (unlike weight). Mass-energy equivalence states that mass and energy are interconvertible (E = mc²).
Examples in the real world
A 1 kg mass on Earth weighs approximately 9.8 N, but on the Moon it weighs only 1.6 N while retaining its exact 1 kg mass.