On the Vis viva. 271 
whole force accumulated in a body by the 
action of any motive force, which puts that 
body into motion. 
Axioms, or Maxims derived from universal 
Experience. 
1. Forces are magnitudes, consequently two 
forces of the same kind have a ratio the one 
to the other. 
2. If two bodies, which are equal and alike 
in all respects, move with equal velocities ; 
their vires vive are also equal. 
3. A motive or retarding force is equal to 
a force, which, by acting in a contrary direc- 
tion, would preserve the body, thus acted on, in 
a state of uniform motion or rest. 
4. The vis viva of a body is equal to the 
quantity of resistance, which it is able to 
overcome. 
THEOREMS, 
THeorem I. If two bodies, A and B, 
move with equal velocities, their vires vive 
will be directly as their masses or quantities 
of matter; that is, put F=vis viva of A; 
f = vis viva of B; a= massof A; b = mass 
of B; and we have as F:f:: a: 6. vi 
For let ¢ be a mass which measures aand 6b, 
and let g be its vis viva when it moves with 
