Bilingual edition: English is preserved and Chinese follows each unit. Terminology uses the confirmed v20260916 glossary; automated semantic review remains traceable. 中英双语版:英文原文完整保留,中文紧随对应单元;术语采用 v20260916 确认表,自动语义审校结果可追溯。
Moment of Inertia: Hoop
转动惯量:环形
The moment of inertia of a hoop or thin hollow cylinder of negligible thickness about its central axis is a straightforward extension of the moment of inertia of a point mass since all of the mass is at the same distance R from the central axis.
For mass M = kg,
internal radius a = cm
and external radius b = cm,
the moment of inertia I = kg m2.
This may be compared with a solid cylinder of equal mass where I(solid) = kg m2, or with a thin hoop or thin-walled cylinder where I(thin) = kg m2.
The moment of inertia of a hollow circular cylinder of any length is given by the expression shown.
对于质量 M = kg,内半径 a = cm 和外半径 b = cm,转动惯量 I = kg m²。这可以与质量相同的实心圆柱体进行比较,其中实心圆柱的转动惯量 I(solid) = kg m²,或与薄环或薄壁圆柱进行比较,其中薄环的转动惯量 I(thin) = kg m²。任何长度的空心圆柱的转动惯量由所示表达式给出。