What is the mass?

The mass is a fundamental property of matter. It is a quantitative measure of the amount of matter in an object. The SI unit for mass is the kilogram (kg). Mass is different than weight, which is the force exerted on an object by gravity. The mass of an object remains constant regardless of its location in the universe, whereas its weight may vary based on the strength of the gravitational force acting upon it. Mass can be measured using various devices, such as a balance or a scale. It is an important quantity in physics, as it affects an object's inertia and gravitational interactions with other objects.