Final answer:
The relative mass of an object is the amount of matter it contains and is measured in kilograms, typically by comparison with the standard kilogram. This quantity does not vary with location, distinguishing it from weight, which changes with gravity.
Therefore, the correct option is A
Step-by-step explanation:
The relative mass of an object refers to the amount of matter an object is made up of. This quantity does not change regardless of location; whether an object is on Earth, in orbit, or on the surface of the Moon, its mass remains constant. Therefore, the concept of relative matter or relative mass generally pertains to comparisons of mass between different objects without the influence of gravitational forces, which would affect weight instead.
In contrast to mass, weight is a force that results from the action of gravity on mass, and therefore, it can vary based on where an object is in relation to a gravitational source. For example, an object will weigh less on the Moon than on Earth due to the lower gravitational force. Inertia is also directly related to mass, where more massive objects have greater inertia, making them harder to start or stop moving.
Mass is commonly measured in kilograms and is determined operationally by comparison with the standard kilogram rather than by counting individual atoms and molecules. When comparing the mass of two objects of the same mass, such as a kilogram of cotton balls and a kilogram of gold, they are equal; however, they differ in volume and density.