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 p ...
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 oppose ...
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 t ...
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. More ...
ially over an area.
Equations for surface force
Surface force due to pressure
:
, where ''f'' = force, ''p'' = pressure, and ''A'' = area on which a uniform pressure acts
Examples
Pressure related surface force
Since pressure is
, and area is a
,
:a pressure of
over an area of
will produce a surface force of
.
See also
*
Body force
In physics, a body force is a force that acts throughout the volume of a body.
Springer site - Book 'Solid mechanics'preview paragraph 'Body forces'./ref>
Forces due to gravity, electric fields and magnetic fields are examples of body forces. Bo ...
*
Contact force
A contact force is any force that occurs as a result of two objects making contact with each other. Contact forces are ubiquitous and are responsible for most visible interactions between macroscopic collections of matter. Pushing a car or kickin ...
Classical mechanics
Fluid dynamics
Force
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