Two discs A and B each of radius r and mass m are attached as shown to form a system. The moment of inertia of this system about an axis perpendicular to the plane of the discs and passing through the center of disc A is

Step-by-step solution

The moment of inertia of the disc about the centroidal axis is m r^2 2 The moment of inertia of the disc at A about the axis passing through B is given using the parallel axis theorem as m r^2 2 +m(2 r)^2 Thus, the total moment of inertia of the whole system is given as m r^2 2 + m r^2 2 +m(2 r)^2=5 m r^2