Surface force denoted ''f_s'' is the

force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...

that acts across an internal or external surface element in a material body. Surface force can be decomposed into two perpendicular components:

normal force In mechanics, the normal force F_n is the component of a contact force that is perpendicular to the surface that an object contacts, as in Figure 1. In this instance '' normal'' is used in the geometric sense and means perpendicular, as oppos ...

s and

shear force In solid mechanics, shearing forces are unaligned forces acting on one part of a body in a specific direction, and another part of the body in the opposite direction. When the forces are collinear (aligned with each other), they are called ...

s. A normal force acts normally over an area and a shear force acts

tangent In geometry, the tangent line (or simply tangent) to a plane curve at a given point is the straight line that "just touches" the curve at that point. Leibniz defined it as the line through a pair of infinitely close points on the curve. Mo ...

ially over an area.

Equations for surface force

Surface force due to pressure

f_s=p \cdot A  \

, where ''f'' = force, ''p'' = pressure, and ''A'' = area on which a uniform pressure acts

Examples

Pressure related surface force

Since pressure is

\frac=\mathrm

, and area is a

(length)\cdot(width) = \mathrm= \mathrm

, :a pressure of

5\ \mathrm = 5\ \mathrm

over an area of

20\ \mathrm

will produce a surface force of

(5\ \mathrm) \cdot (20\ \mathrm) = 100\  \mathrm

Equations for surface force

Surface force due to pressure

Examples

Pressure related surface force

See also