3.6 Mass and Weight
Commonly, we consider mass and weight as the same quantities, but scientifically they are two different quantities. When we say that the weight of an object is 5 kg, it is not true. In fact, 5 kg is the mass of the object.
The simplest definition of mass is that it is a measure of the quantity of matter in a body. Scientifically, the mass of a body can be defined as:
lightbulbThe characteristic of a body which determines the magnitude of acceleration produced when a certain force acts upon it is known as the mass of the body.
Mass is a scalar quantity. It remains the same everywhere. Practically, mass is measured by an ordinary balance. The SI unit of mass is the kilogram (kg).
Weight is a gravitational force acting on the object. It is a vector quantity directed downward, towards the centre of the Earth.
lightbulbThe weight of an object is equal to the force with which the Earth attracts a body towards its centre.