Question

Moment of inertia of a ring about a transverse axis passing through its centre is I. moment of inertia of the ring about an axis coinciding with a tangent in the plane of the ring is

• A. $0.5I$
• B. $2I$
• C. $1.5I$
• D. $1.25I$

Answer 1

Answer: (C)

$1.5I$

$\begin{array}{c}\text{Moment of Inertia about axis of ring}I=m{R}^2\\ \text{by Parallel axis theorem we can find at}\\ \text{the tangent.}\\ \begin{array}{cc}=\frac{m{R}^2}{2}+m{R}^2& =\frac{3m{R}^2}{2}\\ & =1.5I\end{array}\\ \text{Hence option}C\text{is correct}\end{array}$