Question: The diagram shows a uniform rod AB resting in the angle between a vertical plane and a plane inclined at 60° to the vertical. Find the angle θ if:(a) both planes are smooth,(b) the inclined plane is smooth but the vertical plane is rough, A is on the point of slipping down and μ=12.

The diagram shows a uniform rod $AB$resting in the angle between a vertical plane and a plane inclined at $60°$to the vertical. Find the angle $\theta$if:

$($a$)$both planes are smooth,

$($b$)$the inclined plane is smooth but the vertical plane is rough, $A$is on the point of slipping down and $\mu =\frac{1}{2}.$