Mathematics 9709/43 — October/November 2012

$ABCD$ is a semi-circular cross-section, in a vertical plane, of the inner surface of half a hollow cylinder of radius $2.5\text{ m}$ which is fixed with its axis horizontal. $AD$ is horizontal, $B$ is the lowest point of the cross-section and $C$ is at a height of $1.8\text{ m}$ above the level of $B$ (see diagram). A particle $P$ of mass $0.8\text{ kg}$ is released from rest at $A$ and comes to instantaneous rest at $C$.