The triangle shown in Figure 1-2 is a convenient memory device for
the force-area-pressure formulas.
It helps you recall the three
factors involved: F, A, and P.
Because the F is above the line in
the triangle, it also reminds you that in both formulas indicating
division, F is always divided by one of the other two factors.
Figure 1-2.
Relationship of Force, Area, and Pressure.
TRANSMISSION OF FORCE
Two means of transmitting force are through solids and through
liquids.
Since this text is on hydraulics, the emphasis is on
fluids.
Force transmission through solids is presented only as a
means of comparison.
Transmission of Force Through Solids. Force applied at one point
on a solid body follows a straight line undiminished to an opposite
point on the body. This is illustrated in Figure 1-3.
Transmission of Force Through Confined Liquids.
Applied forces
are transmitted through bodies of confined liquids in the manner
described by Pascal's Law.
This law of physics, formulated in the
seventeenth century by the French mathematician Blaise Pascal,
states: pressure applied to any part of a confined liquid is
transmitted without change in intensity to all parts of the liquid.
This means that wherever it is applied on the body of liquid, pressure
pushes equal force against every square inch of the interior surfaces
of the
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