Find the volume $of$ the solid whose base $is$ the region bounded $by$ the $x-$axis and the curve $y=\sqrt[\phantom{2}]{cos(\frac{x}{5})}$ for $x$ varying between $x=\frac{-5}{2}$ and $x=\frac{5}{2}$ and which has the property that each cross section

perpendicular $to$ the $x-$axis $is$ a semicircle.

Volume $=$