The conservation of mechanical energy states that:

Where K is the kinetic energy and U is the potential energy. We know that the potential energy is given as:

and the potential energy is given as:

We know that in point A the velocity is zero, then the kinetic energy in that point is zero. We also know the heights in point A and F then we can plug the vaus we know in the conservation of energy and solve for the velocity in point F:
![\begin{gathered} mgh_A=(1)/(2)mv^2+mgh_F \\ gh_A=(1)/(2)v^2+gh_F \\ gh_A-gh_F=(1)/(2)v^2 \\ v^2=2(gh_A-gh_F) \\ v=\sqrt[]{2g(h_A-h_F)} \\ v=\sqrt[]{2(9.8)(30-15)} \\ v=\sqrt[]{294} \\ v=17.15 \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/b29m7zck5auvmujsleb3qvs8vmjbf51q0u.png)
Therefore the velocity in point F is 17.15 m/s