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Fig. 1-4.

Concentrated Force. A concentrated force represents the effect
of a loading which is assumed to act at a point on a body. We can
represent a load by a concentrated force, provided the area over which
the load is applied is very small compared to the overall size of the
body. An example would be the contact force between a wheel and the
ground.
Distributed forces loading. Sometimes, a body may be
subjected to a loading that is distributed over its surface. For example,
the pressure of the wind on the face of a sign, the pressure of water
within a tank, or the weight of sand on the floor of a storage container,
are all distributed loadings. The pressure exerted at each point on the
surface indicates the intensity of the loading. It is measured using
/
pascals Pa ( Nm ) in SI units.
2
Uniform Loading Along a Single Axis. The most common type
of distributed loading encountered in engineering practice is generally
uniform along a single axis. For example, consider the beam (or plate)
in Fig. 1-5,a that has a constant width and is subjected to a pressure
loading that varies only along the x axis. This loading can be
/
2
described by the function p = p ()x N m . It contains only one
variable x, and for this reason, we can also represent it as a coplanar
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