Question

A circular thin disc of mass $2kg$ has a diameter of $0.2m$. Calculate its moments of inertia about an axis passing through the edge and perpendicular to the plane of the disc (in $kg-m^2$)

• A. $0.01$
• B. $0.03$
• C. $0.02$
• D. $3$

Answer 1

The correct option is B $0.03$

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

$=\frac{3}{2}m{r}^2$

$=\frac{3}{2}\times 2\times {\left(\frac{0.2}{2}\right)}^2$

$=3\times 0.1\times 0.1$

$=0.03$