A uniform rod of length 5 m is placed against the wall as shown. If coefficient of friction $\mu$ is the same for both the walls, the minimum value for $\mu$ not to slip.

Question

$$\begin {array} {1 1} (a)\;\mu=\frac{1}{2} & \quad (b)\;\mu=\frac{1}{4} \\ (c)\;\mu=\frac{1}{3} & \quad  (d)\;\mu=\frac{1}{5} \end {array}$$