Pappus, Composite and Advanced Solids — Worked Examples
These examples emphasize method selection: direct formula, centroid-based revolution, geometric decomposition, exact prismatoidal evaluation, or numerical integration from measured sections.
Example 1: Volume of an ellipsoid
An ellipsoidal tank has semi-axes , , and . Determine its geometric volume.
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0 of 2 Steps CompletedExample 2: Ring torus volume and surface area
A ring torus has major radius and tube radius . Determine its volume and surface area.
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0 of 2 Steps CompletedExample 3: Derive torus volume using Pappus
A circle of radius is revolved about an external coplanar axis from the circle center. Use Pappus-Guldinus to determine the generated volume.
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0 of 2 Steps CompletedExample 4: Derive torus surface area using Pappus
Use Pappus-Guldinus to determine the surface area generated when a circle of radius is revolved about the same external axis from its center.
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0 of 2 Steps CompletedExample 5: Generate a sphere from a semicircular area using Pappus
A semicircular area of radius is revolved through about its bounding diameter. Use Pappus-Guldinus to determine the generated volume.
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0 of 2 Steps CompletedExample 6: Pappus surface theorem with a semicircular arc
A semicircular wire arc of radius is revolved about a coplanar line parallel to its diameter and located from the diameter on the side opposite the arc. Determine the generated surface area.
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0 of 2 Steps CompletedExample 7: Exact prismatoidal volume of a square frustum
A square frustum has end areas and . The corresponding side lengths are therefore and . Its height is . Determine the volume using the prismatoidal formula.
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Five equally spaced cross-sections are apart and have areas , , , , and . Estimate the enclosed volume using the composite trapezoidal rule.
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Use the five equally spaced areas from Example 8 to estimate volume with Simpson's rule.
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0 of 3 Steps CompletedExample 10: Reject Simpson's one-third rule for unequal spacing
Four measured cross-sections occur at stations , , , and . Their areas are known, but the spacing is not uniform. Determine whether the equal-spacing composite Simpson's formula from the lesson may be applied directly.
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A tank consists of a vertical cylinder of radius and height topped by a hemisphere of the same radius. Determine its total internal geometric capacity.
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A rectangular concrete block measures . A cylindrical opening of radius is bored completely through the dimension. Determine the remaining concrete volume.
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0 of 3 Steps CompletedAdvanced-method check
Pappus requires the correct curve or area centroid and a valid axis of revolution. Simpson's rule requires equal spacing and an even number of intervals. Composite surface area requires a separate exposed-surface inventory; it cannot be obtained by blindly adding component total areas.