Solids of revolution — egg-shaped forms Which solid is generated by revolving an ellipse about one of its principal axes, producing an egg-like (spheroidal) shape used in product and aerodynamic design?
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AEllipsoid
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BTorus
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CCone
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DCylinder
Answer
Correct Answer: Ellipsoid
Explanation
Introduction / Context:Many engineering shapes are created as solids of revolution due to manufacturing practicality and favorable structural/aerodynamic properties. Revolving conic sections yields common primitives used in modeling and analysis.
Given Data / Assumptions:
- The curve is an ellipse.
- The operation is revolution about one of the ellipse’s axes.
- The result is described as egg-shaped or spheroidal.
Concept / Approach:Revolving an ellipse about its major or minor axis yields an ellipsoid (specifically, a prolate or oblate spheroid). This form appears in pressure vessels, lenses, and streamlined bodies.
Step-by-Step Solution:Identify the base curve: ellipse.Recognize that revolving an ellipse does not produce a torus (circle around an external axis), cone (triangle around an edge), or cylinder (rectangle around a side).Conclude the correct solid is an ellipsoid.
Verification / Alternative check:CAD systems label this feature “revolve” of an ellipse to create a spheroid/ellipsoid. Mathematical definitions align with surfaces of constant sum of distances to two foci.
Why Other Options Are Wrong:
- Torus: generated by revolving a circle about an axis offset from the circle.
- Cone: generated by revolving a right triangle.
- Cylinder: generated by revolving a rectangle about one side.
Common Pitfalls:Calling all egg-like bodies “spheres”—a sphere is a special ellipsoid with equal axes.
Final Answer:Ellipsoid