Question

What is meant by the mass of a body? What is the SI unit of mass?

Answer 1

1. The total quantity of matter contained in an object is called its mass.
2. In other words, mass is a measure of the number of atoms contained in any object.
3. The SI unit of mass is the kilogram $\left(kg\right)$. And it is a scalar quantity.
4. Mass is an intrinsic, unchanging property of matter.
5. Since the number of atoms in any object remains constant, hence its mass remains constant.

Thus, the total quantity of matter contained in an object is called its mass and its SI unit is kilogram $\left(kg\right)$.