Consider the Nordex 1.3 MW, 60-m diameter, wind turbine with operating conditions and output power given in the table below, located in an area with 8 m/s average wind speeds. a. Find the average power in the wind (W/m2 ) assuming Rayleigh statistics. b. Create a spreadsheet determine the energy delivered (kWh/yr) from this machine. c. What would be the average efficiency of the wind turbine? d. If the turbine’s rotor operates at 70% of the Betz limit, what is the efficiency of the gearing and generator?

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Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

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