variations. The mass contained in one cubic centimeter is designated 
as density, e , and dlmensionally is equal to gram-mass/cm . How- 
ever, it is to Newton (1643-1727) to whom the world is under great 
Hcrations for the dlscoverv of certain natural laws and establishment 
of certain new sciences. Among the natural laws discovered 
are the Law of Gravitation and the statement (Second Newton 
that the force is proportional to the rate of change of momen 
Mathematically it can be e^ressed as: 
whe re : 
F = ^^(mv) = m— =ma 
Fat 
= K 
'°l°^2 
r2 
F = Force 
Fat = Force of attraction 
V = Velocity of a moving body 
a = Acceleration of a moving body 
I = Constant of gravitation = 66.7x10' cg.s 
mj = Mass of the first body 
m2 - Mass of the second body 
r = Distance between the centers of the m^^ and m2 
masses. 
X ■ 
Near the surface of the earth all the physical bodies ^^^^^ 
support will fall toward the earth with a certain acceleration, due to the 
presence of attraction between the mass of the body and the mass of 
2 
