Q. A uniform rod AB of mass M and length $\sqrt{2}$ R is moving in a vertical plane inside a hollow sphere of radius R. The sphere is rolling on a fixed horizontal surface without slipping with velocity of its centre 2v. When the end B is at the lowest position, its speed is found to be v as shown in the figure. If kinetic energy of the rod at this instant is $\frac{4}{K}M{v}^2$. Find K.