A wind turbine with a rotor diameter of 55 m is rated at 1 MW at a hub height wind speed of 14 m/s. It has a cut-in speed of 4 m/s and a cut-out speed of 25 m/s. Assume that this machine is located at a site where the mean wind speed is 10 m/s and that a Rayleigh wind speed distribution can be used. Calculate the following: (a) The number of hours per year that the wind is below the cut-in speed. (b) The number of hours per year that the machine will be shut down due to wind speeds above the cut-out velocity. (c) The energy production (kWh/year) when the wind turbine is running at rated power.