How does the polar moment of inertia of a hollow circular section about a central perpendicular axis compare to its transverse horizontal axis moment of inertia________________?
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Answer: B. double
Explanation
Perpendicular axis theorem states that polar moment of inertia equals the sum of two orthogonal transverse moments. For a symmetrical hollow circular section, the two orthogonal transverse moments of inertia are equal. Adding two identical transverse moments together results in a polar moment that is exactly double either one. Polar moment of inertia measures an object ability to resist torsional deformation along a central axis. Cross-sectional symmetry ensures that transverse moments of inertia about perpendicular diametrical axes are identical. Calculations for circular shafts in torsion rely heavily on polar moment properties.
Option A incorrectly assumes the polar moment equals a single transverse moment without orthogonal addition. Option C suggests the polar moment is half, which reverses the correct additive relationship of the theorem. Option D incorrectly multiplies the transverse moment by four instead of applying the proper sum of two axes.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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