Question

$M.I$ of solid sphere about a tangent is $70kg{m}^2$. If $M.I$ of the sphere about a diameter is:

• A. $20kg{m}^2$
• B. $10kg{m}^2$
• C. $50kg{m}^2$
• D. $25kg{m}^2$

Answer 1

The correct option is A $20kg{m}^2$

Moment of inertia of a solid sphere through a tangent is $\frac{2}{5}M{r}^2+M{r}^2=\frac{7}{5}M{r}^2=70$

$M{r}^2=50$

Moment of inertia of the solid sphere through the diameter is $\frac{2}{5}M{r}^2=20$kgm/s²