Kinematics of motion in a straight line — practice question

$ABC$ lies along the line of greatest slope on a plane inclined at angle $\alpha$ to the horizontal, with $\sin\alpha = 0.28$ and $\cos\alpha = 0.96$. Point $A$ is at the top of the plane, point $C$ is at the bottom of the plane, and $AC$ has length $5\,\text{m}$. The section of the plane above the level of $B$ is smooth, while the section below the level of $B$ is rough. A particle $P$ is released from rest at $A$ and reaches $C$ with speed $2\,\text{m s}^{-1}$. The coefficient of friction between $P$ and the part of the plane below $B$ is $0.5$.