Summary
Fbouyant = wliquid
Several different systems of units are in common useage when dealing with pressure:
1 pascal = 1 Pa = 1 [ N / m2 ]
1 atm = 1.013 x 105 Pa
1 bar = 100 kPa = 1 x 10 5 Pa
1 atm = 1.013 bar
1 atm = 101.3 kPa
1 mm Hg = 133 Pa
1 atm = 760 mm Hg
1 Torr = 1 mm Hg
1 atm = 760 Torr (Units of pounds per square inch (PSI) are also commonly used but we will avoid those in this course).
1 A 1 v1 = 2 A 2 v2 For many situations -- for most situations involving a liquid but not a gas -- we can assume the density does not change. This is called an incompressible fluid. For those cases,
A 1 v1 = A 2 v2
(1/2) v2 + P + g y = constantor
(1/2) 1 v12 + P1 + 1 g y1 = (1/2) 2 v22 + P2 + 2 g y2 If the vertical height y does not change, this means
(1/2) v2 + P = constant
or
(1/2) 1 v12 + P1 = (1/2) 2 v22 + P2 (c) 2005, Doug Davis; all rights reserved
Bouyancy Homework Return to ToC, Fluids