Give a note on mass.

The mass of a body is the quantity of matter (or material) contained in it. Mass is a scalar quantity and it is measured by an ordinary equal arm balance. The unit of mass is kilogram. A body contains the same quantity of matter wherever it be-whether on the earth, moon or even in outer space. Thus, the mass of a body is constant and does not change from place to place. Mass of a body is usually denoted by the small 'm'. Mass of a body is a measure of inertia of the body and hence it is also known as inertial mass. The mass of a body cannot be zero.