Torricelli's Law
Revision as of 19:01, 10 December 2007 by Temperal (talk | contribs) (Torricelli's Law moved to Torricelli's law: capitalization)
Torricelli's Law, named after Evangelista Torricelli, relates initial velocity, gravity, and height to the flow of a liquid out of an opening:
where
is the speed out of the opening,
the initial speed,
gravity, and
the distance from the top of the hole to the top of the liquid.
Derivation
Torricelli's Law may be derived by considering the mass of water at the top of the liquid. This water has potential energy
relative to the hole and kinetic energy
, for total energy of
. At the level of the hole, this water will have converted all potential energy into kinetic energy, so the total energy will now be
. By the First Law of Thermodynamics,
, so
; solving for
,