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THEOREMS anp PROBLEMS, 
INTENDED 
To elucidate the mechanical principle called 
VIS VIVA. 
BY MR. JOHN GOUGH. 
(Communicated by Dr. Houme.) 
swe 
DEFINITIONS. 
1. Force is an abstract term comprising 
motive force, retarding force, resistance, and 
the vis viva of mathematicians on the con- 
tinent. 
2. Motive force is any force, that increases 
the motion of a body on which it acts. 
3. Retarding force is any force that dimi- 
nishes the motion of a body subjected to its 
influence. 
A. Resistance is a force constantly exerted 
by a body, when affected by pressure or 
percussion, to preserve its figure unchanged. 
5. Quantity of resistance is the whole force 
thus exerted by a body, while its figure is 
undergoing a certain change. 
6. Vis viva is the whole force opposed by 
a body in motion, to a retarding force which 
impedes its progress : and, conversely, it is the 
1 
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