question_answer

A circular disc \[{{D}_{1}}\] of mass M and radius R has two identical discs \[{{D}_{2}}\] and \[{{D}_{3}}\]of the same mass M and radius R attached rigidly at its opposite ends (see figure). The moment of inertia of the system about the axis OO’, passing through the centre of \[{{D}_{1}}\], as shown in the figure, will be-                                                                                                                          [JEE Main 11-Jan-2019 Evening]

A)  \[3M{{R}^{2}}\]        

B)       \[\frac{4}{5}M{{R}^{2}}\]

C)  \[\frac{2}{3}M{{R}^{2}}\]     

D)       \[M{{R}^{2}}\]

Correct Answer: A

Solution :

[a]