The basic equation of fluid statics (continued)
2-Now, let us calculate pressure–gradient in a static fluid.
Identify all forces: pressure forces, and external body force which is gravity in the present case.Consider a differential fluid elemental volume, .
Force Balance (in vector form ) (pressure force + gravitational force) = 0
or, or, (form previous lecture) or, This is the basic (vector) equation for fluid statics.
The equation in the scalar form: : x direction : y direction : z direction
Where,
or where
. 
(pressure force + gravitational force) = 0 
(form previous lecture)
: x direction
: y direction
: z direction 
or 
