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
Where,
ρ = density and
v = the volume
The weight mass formula is given as
m = w / g
Where,
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
Where,
F = force
G = gravity
According to Einstein’s mass-energy relation
m = (E / c2)
Where,
m = mass
E = energy
c = speed of light (3×108 m/s)
The kinetic energy mass formula is given as
K.E = ½ mv2
Where,
m = mass,
v = velocity.
Example 1
Calculate the mass if the weight of a body is 80 N.
Solution:
Given,
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.
Solution:
Given:
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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