Q 9 and 10:

9. Two blocks A and B of same mass connected with a spring are placed on a rough inclined plane, which makes an angle $\theta$ with horizontal. What minimu velocity should be given to A up the incline so that B just move ?
$$\begin{gathered} \left(A\right) \sqrt{\frac{m}{K}}\left(g \sin \theta +\mu g\cos \theta \right) \left(B\right) \sqrt{\frac{2m}{K}}\left(g \sin \theta +\mu g\cos \theta \right) \\ \left(C\right) \sqrt{\frac{3m}{K}}\left(g \sin \theta +\mu g\cos \theta \right) \left(C\right) \left(A\right) 2\sqrt{\frac{m}{K}}\left(g \sin \theta +\mu g\cos \theta \right) \end{gathered}$$