Concept of Mass

triptiThis article has been authored by Tripti Gupta,who has primarily written Physics articles out here.She tends to make every complex physics concept look dead simple to perplexed minds and has exhaustively written articles, explaining various concepts and phenomenons, here at XAmplified

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It is defined as quantity of matter contained in a body.


The mass of a body is actually the quantity of matter in it, which can never be zero. There are two different kinds of masses of a body

  • Inertial mass
  • Gravitational Mass

The values of the two types of masses of a body are same. Inertial mass of a body is the measure of inertia and gravitational mass of a body is a measure of gravitational pull. The mass of a body is not affected by the presence of other bodies. It also does not change from place to place. It is a scalar quantity. The common unit of mass is kilogram.

Originally, one kilogram was defined as ” the mass of one cubic decimeter of water at 4ºC “.

Later on, this definition got modified to “the mass of the international prototype of the kilogram which is a standard block of Platinum Iridium alloy preserved in the International Bureau of weights and Measures at a serves, near Paris, France”.

Measurement of Mass

The mass of a body can be measured in two different ways. Likewise, mass of a body is of two types as defined below:

Inertial Mass

When a body is in transitional motion under the effect of an external force other than gravity, the mass of the body measured is called its ‘Inertial mass’.

It is found that if a given force produces an acceleration a1  in a body of mass m1 and a2 in a body of mass m2, then

Ratio of Mass & Acceleration

To measure inertial mass of a body, inertial balance is used.

Gravitational Mass

When a body is under the effect of gravity in absence of motion, the mass of the body under observation is called ‘Gravitational Mass’. It is measured by using Physical balance.


  1. Pradeep’s Fundamental (XI)
  2. Modern’s ABC of Physics (XI)