Question

A small spheres of mass 10kg and 30kg are joined by a rod of length 0.5m and of negligible mass. The M.I. of the system about an axis passing through centre of rod and normal to it is

• A. $10kg{m}^2$
• B. $2.5kg{m}^2$
• C. $20kg{m}^2$
• D. $8{kgm}^2$

Answer 1

The correct option is B $2.5kg{m}^2$

The $M.I.$ of the system about a normal axis through centre of the system is $:$

$I=m_1{r_1}^2+m_2{r_2}^2$

$=10\times {\left(0.25\right)}^2+30\times {\left(0.25\right)}^2$

$=40\times {\left(0.25\right)}^2$

$=2.5kg.m^2$

Hence,

option $\left(B\right)$ is correct answer.