Rotational Motion

Four identical uniform solid spheres each of same mass '\(M\)' and radius '\(R\)' are placed touching each other as shown in figure, with centres A, B, C, D. \(\mathrm{I}_{\mathrm{A}}, \mathrm{I}_{\mathrm{B}}, \mathrm{I}_{\mathrm{C}}\) and \(\mathrm{I}_{\mathrm{D}}\) are the moment of inertia of these spheres respectively about an axis passing through centre and perpendicular to the plane. The difference in \(\mathrm{I}_{\mathrm{A}}\), and \(\mathrm{I}_{\mathrm{B}}\) is