Kinematics of motion in a straight line — practice question

A particle $P$ with mass $3\,\text{kg}$ is fired with speed $8\,\text{m s}^{-1}$ up the line of greatest slope of a rough plane inclined at $30^\circ$ to the horizontal. $P$ is launched from a point $A$ on the plane and reaches instantaneous rest at a point $B$ on the plane. $P$ then moves back down the plane. The coefficient of friction between $P$ and the plane is $\frac{1}{12}\sqrt{3}$. Using an energy method throughout, determine the speed of $P$ at the moment it returns to $A$.