Mass Formula

The mass concept measures the quantity of matter existing in an object. It is a quantitative property of an object against the acceleration. The mass and weight of an object are not the same. The molar mass (M) is a physical property and it is defined as the mass of one mole of the chemical substance or it is a ratio of the mass of a chemical compound to its amount of chemical substance. The unit of molar mass is kg/mol.

The mass formula is given as

 Mass =  ρ × v


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

According to Einstein’s mass-energy relation 

m = (E / c2)


m = mass

E = energy

c = speed of light (3×108 m/s)

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 80 N.



weight of the body = 80 N

The mass of the body is expressed by

m = w / g

m = 80 / 9.8

m = 8.163 kg

Example 2

Determine the mass of a body if the K.E is 70 J and velocity is 8m/s.



K.E = 70 J

v = 8 m/s

the mass is expressed by

m = 2 K.E / v2

m = (2 × 70)/ 82

m = 14o/64

m= 2.18 kg




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