Q4:- If the wind speed measured on 10 m height from the earth. What the height of wind turbine tower should be if the turbine work on 5 m/s. Discuss the height from the earth surface with roughness, if the surface are 1. Sandy surface is vary between (0.1 - 0.13).| 2. Trees surface is vary between (0.2- 0.25). 3. Hily surface is vary between (0.5- 0