Energy, work and power — practice question

A block of mass $3\text{ kg}$ is first at rest at the lower end $O$ of a rough plane inclined at angle $\alpha$ to the horizontal, with $\sin \alpha = 0.6$ and $\cos \alpha = 0.8$. A force of magnitude $35\text{ N}$ acts on the block at angle $\beta$ above the plane, where $\sin \beta = 0.28$ and $\cos \beta = 0.96$. The block begins to move up the line of greatest slope of the plane and reaches point $A$ with speed $4\text{ m s}^{-1}$. The distance $OA$ is $12.5\text{ m}$ (see diagram). When the block is at $A$, the force of magnitude $35\text{ N}$ stops acting.