Definify.com
Webster 1913 Edition
Vis
‖
Vis
,Noun.
1.
Force; power.
2.
(Law)
(a)
Physical force.
(b)
Moral power.
Principle of vis viva
(Mech.)
, the principle that the difference between the aggregate work of the accelerating forces of a system and that of the retarding forces is equal to one half the vis viva accumulated or lost in the system while the work is being done.
– Vis impressa
[L.]
(Mech.)
, force exerted, as in moving a body, or changing the direction of its motion; impressed force.
– Vis inertiae
. [L.]
(a)
The resistance of matter, as when a body at rest is set in motion, or a body in motion is brought to rest, or has its motion changed, either in direction or in velocity.
(b)
Inertness; inactivity.
Vis intertiae and inertia are not strictly synonymous. The former implies the resistance itself which is given, while the latter implies merely the property by which it is given.
– Vis mortua
[L.]
(Mech.)
, dead force; force doing no active work, but only producing pressure.
– Vis vitae
, or
Vis vitalis
[L.]
(Physiol.)
, vital force.
– Vis viva
[L.]
(Mech.)
, living force; the force of a body moving against resistance, or doing work, in distinction from vis mortua, or dead force; the kinetic energy of a moving body; the capacity of a moving body to do work by reason of its being in motion. See
Kinetic energy
, in the Note under Energy
. The term vis viva is not usually understood to include that part of the kinetic energy of the body which is due to the vibrations of its molecules.