Energy, work and power — practice question

The diagram represents the vertical cross-section $ABCD$ of a surface. $BC$ is a circular arc, and $AB$ and $CD$ are tangents to $BC$ at $B$ and $C$ respectively. $A$ and $D$ are at the same horizontal level, while $B$ and $C$ lie $2.7\text{ m}$ and $3.0\text{ m}$ above the level of $A$ and $D$ respectively. A particle $P$ of mass $0.2\text{ kg}$ is projected from $A$ with speed $8\text{ m s}^{-1}$ in the direction of $AB$. The parts of the surface containing $AB$ and $BC$ are smooth. The section containing $CD$ applies a constant frictional force to $P$ as it travels from $C$ to $D$, and $P$ is at rest when it reaches $D$.