The wind flows over a rough terrain and the boundary layer is defined as $u / U=y /(y+0.01),$ where $y$ is in meters. If the free stream velocity of the wind is $18 \mathrm{~m} / \mathrm{s}$, determine the velocity at an elevation $y=0.2 \mathrm{~m}$ and at $y=0.5 \mathrm{~m}$ from the ground surface.