Definition of Terms, Continued
Solids
(Continued)
Cylinders are two parallel bases formed by a fixed curve or directrix
revolving around a straight line or generatrix at the center. The generatrix at
the center of the cylinder is also called an axis. The height of the cylinder is
called the altitude. Any point along the edges of the cylinder is referred to as
an element. Right circular cylinders have lateral edges perpendicular to the
bases and oblique circular cylinders have lateral edges oblique to the bases.
Moving a point around and along the surface of a cylinder with uniform
angular velocity to the axis and with a uniform linear velocity in the direction
of the axis produces a helix.
You may construct a helix using a cylinder or
cone.
Figure 2-12 show examples of cylinders and a helix.
Figure 2-12.—Cylinders and a helix.
Continued on next page
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