Surface force
Surface force denoted fs is the force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

 that acts across an internal or external surface element in a material body. Surface force can be decomposed in to two perpendicular components: pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

 and stress
Stress (physics)
In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...

Pressure force acts normally
Surface normal
A surface normal, or simply normal, to a flat surface is a vector that is perpendicular to that surface. A normal to a non-flat surface at a point P on the surface is a vector perpendicular to the tangent plane to that surface at P. The word "normal" is also used as an adjective: a line normal to a...

 over an area and stress force acts tangent
In geometry, the tangent line to a plane curve at a given point is the straight line that "just touches" the curve at that point. More precisely, a straight line is said to be a tangent of a curve at a point on the curve if the line passes through the point on the curve and has slope where f...

ially over an area.

Surface force due to pressure

f = Force, p = pressure, A = cross sectional area of the moving fluid

Pressure related surface force

Pressure is in

Area is a

Given a pressure of and an area of find the surface force due to pressure.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.