Question

Four identical discs each of mass ‘M’ and diameter ‘a’ are arranged in a small plane as shown in the figure. If the moment of inertia of the system about OO’ is ($\frac{x}{4}$) Ma2. Then, the value of x will be _______.

Answer 1

I=$2\times\frac{Ma^2}{\frac{2}{4}}$+$2\times\frac{Ma^2}{\frac{2}{4}}$+$\frac{Ma^2}{2}$
=$\frac{Ma^2}{8}$+5$\frac{Ma^2}{8}$
=6$\frac{Ma^2}{8}$
=$\frac{3}{4}$ Ma2