The profile of a dam is an arc of a circle,the arc having a radius of 30m and subtending an angle of $60^{\large\circ}$ at the centre of curvature which lies in the water surfaces.Determine the load on the dam in N/m

Question

$\begin{array}{1 1}(A)\;5.2\times 10^6N/m\\(B)\;4.28\times 10^6N/m\\(C)\;5.8\times 10^6N/m\\(D)\;7.3\times 10^5N/m\end{array} $