Question

The moment of inertia of a solid cylinder of radius $a$, mass $M$ and height $h$ about an axis parallel to the axis of the cylinder and at distance $b$ from its centre is :
[Assume $b>a$]

• A. $\frac{1}{2}M(a^2+2b^2)$
• B. $\frac{1}{2}M(2a^2+b^2)$
• C. $\frac{1}{2}M(a^2+b^2)$
• D. $\frac{1}{2}M(\frac{a^2}{3}+\frac{b^2}{12})$

Answer 1

The correct option is A $\frac{1}{2}M(a^2+2b^2)$

Using parallel axis theorem,


$I_{A{A}^{\prime }}=I_{x{x}^{\prime }}+M{b}^2$
$\Rightarrow I_{A{A}^{\prime }}=\frac{M{a}^2}{2}+M{b}^2$
$\Rightarrow I_{A{A}^{\prime }}=\frac{M}{2}(a^2+2b^2)$