Mass and weight – the two terms that co-relate and confuse us a lot. People often get confused and consider both mass and weight means same, however, they are far away from reality. These two terms sure do relate but they have completely different meaning, especially in terms of physics.
It is defined as the amount of matter contained in an object. This definition is not considered as the true and complete definition of mass. So mass can be defined in terms of inertia.
Inertia is the resistance to any change in the state of motion of an object. This includes the change of speed, distance or object which is initially at rest. The standard unit of mass is kilogram (Kg). Moreover, mass remains unchanged regardless of its position in the space.
The law of universal gravitation states that two masses attract each other with the force proportional to it. However, there is no effect of force on the magnitude of the mass. A person having a mass of 70 kg will have the same mass of 70 kg on other planets as well.