Question

The moment of inertia of a uniform ring of mass $ m $ and radius r about an axis, $ AA $ touching the ring tangentially and lying in the plane of the ring only, as shown in figure , is

• A. $ \frac{5}{4}m{{r}^{2}} $
• B. $ \frac{5}{2}m{{r}^{2}} $
• C. $ \frac{1}{4}m{{r}^{2}} $
• D. $ \frac{1}{2}m{{r}^{2}} $

Answer 1

Answer: (A)

By parallel axis theorem, $ I={{I}_{cm}}+m{{h}^{2}} $ $ =\frac{m{{r}^{2}}}{4}+m{{r}^{2}} $ $ =\frac{5}{4}m{{r}^{2}} $