Energy, work and power — practice question

The figure shows a vertical cross-section $ABC$ of a surface. The section of the surface along $AB$ is smooth, and $A$ lies $2.5$ m above the level of $B$. The section of the surface along $BC$ is rough and makes an angle of $45^\circ$ with the horizontal. The length of $BC$ is $4$ m (see diagram). A particle $P$ of mass $0.2$ kg is released from rest at $A$ and moves while remaining in contact with the curve $AB$ and then the straight line $BC$. The coefficient of friction between $P$ and the section of the surface along $BC$ is $0.4$.