Question

Four particles each of mass $1kg$ are at the four corners of a square of side $1m$. The $M.I$ of the system about a normal axis through centre of square is

• A. $6kg{m}^2$
• B. $1.2kg{m}^2$
• C. $2kg{m}^2$
• D. $2.5kg{m}^2$

Answer 1

The correct option is C $2kg{m}^2$

Side of square=1m

Distance between centre and corner=$\frac{1}{\sqrt{2}}$m

I=$\sum M_i{R}_i^2$

I= $1(\frac{1}{\sqrt{2}}{)}^2+1(\frac{1}{\sqrt{2}}{)}^2+1(\frac{1}{\sqrt{2}}{)}^2+1(\frac{1}{\sqrt{2}}{)}^2=2kg{m}^2$