We have learnt in the previous chapter that the mass of an object is the measure of its inertia
. We have also learnt that greater the mass, the greater is the inertia. It remains the same whether the object is on the earth, the moon or even in outer space. Thus, the mass of an object is constant and does not change from place to place.
Mass is the quantity of matter in a physical body. It is also a measure of the body’s inertia.
S I unit of mass is kg.
C G S unit of mass is g.
Mass is a scalar quantity, it has only magnitude no direction.
It is measured by Beam balance.
It is constant everywhere. mass is not the same as weight in physics. Due to the lower gravity on the Moon, an object would weigh less than it does on Earth while maintaining the same mass. This is so because mass is a force, but weight is not.