c
The distance of \(10\) \(\mathrm{m}\) on the hypotenuse on an incline of \(30^{\circ}\) corresponds to a height difference of \(5.\) Thus change in potential energy is given as \(5mg.\)

The change in the kinetic energy is given as

\(\frac{1}{2} m v^{2}+\frac{1}{2} I \omega^{2}\)

moment of inertia of a hollow cylinder about centroidal axis is \(m r^{2}\)

Thus we get the kinetic energy as

\(\frac{1}{2} m v^{2}+\frac{1}{2} m r^{2} \frac{v^{2}}{r^{2}}\)

or

\(m v^{2}\)

Equating both the energies we get

\(5 m g=m v^{2}\)

or

or \(v=\sqrt{49}=7 m / s\)