A wind turbine with a 50-m-diameter rotor is rotating at 25 rpm under steady winds at an average velocity of 10 m/s. The electrical power output from the turbine is 375 kW. The combined efficiency of the gearbox/generator is 90 percent. Taking the density of air to be 1.20 kg/m, determine Wind turbine efficiency b. Tip speed of the blade, in km/h c. Air velocity at the turbine exit if the turbine operated ideally at the Betz limit, in m/s. .