what is the definition of mass of an object
Mass Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.[1] It also determines the strength of its mutual gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg).
Density The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is