Mass Formula


Mass Formula

The Mass concept decides the amount of matter is present in an object. It is a quantitative measure of an object’s resistance to acceleration. Not to get confused with the term weight, Weight is not a mass but the amount of gravitational force that acts on the given body.The molar mass, M is the physical property which is defined as the mass of a chemical substance divided by its amount of the substance. The SI unit of molar mass is kg/mol.  

The mass formula is given as


ρ = density and

v = the volume

The weight mass formula is given as

m = w / g


w = weight,

m = mass,

g = gravity

The mass formula is also given as

m = F / a

If acceleration itself is the gravity, then

M = F / g


F = force

G = gravity

The well known Einstein’s mass-energy relation that provides mass energy formula as

m = E / c2


E = energy,

m = mass,

c = speed of light

The kinetic energy mass formula is given as

K.E = ½ mv2


m = mass,

v = velocity.


Example 1

Calculate the mass if the weight of a body is 90 N.



weight of the body = 90 N,

The mass of the body is expressed by

m = w / g

= 90 / 9.8

   = 9.183 kg


Example 2

Determine the mass of a body if the K.E is 60 J and velocity is 7m/s.



Kinetic energy, k.E = 60 J,

Velocity, v = 7 m/s

the mass is expressed by

m = 2 k.E / v2

  = 2 ×60 / 72

  = 2.44 kg


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