Question

A solid cylinder of mass $20kg$ has length $1m$ and radius $0.2$ $m$. Then its moment of inertia(in $kg-m^2$) about its geometrical axis is

• A. $0.8$ $kg-m^2$
• B. $0.4$ $kg-m^2$
• C. $0.2$ $kg-m^2$
• D. $20.0$ $kg-m^2$

Answer 1

The correct option is B $0.4$ $kg-m^2$

Given,

$r=0.2m$

$m=20kg$

The moment of inertia about the geometrical axis of a solid cylinder is,

$I=\frac{1}{2}m{r}^2$

$I=\frac{1}{2}\times 20\times 0.2\times 0.2$

$I=0.4kg-m^2$

The correct option is C.