The following measurements were made at a potential site for a wind farm: The turbines have blade length of 20 m, overall efficiency is 0.3 (constant for all wind speed), the density of air is 1 kg/m3. a) A wind turbine has a cut-in speed at 3 m/s and a cut-out speed at 7 m/s. Find the average speed which the turbine operates at and the average power produced by the turbine. 1 Speed (m/s) hours 0 2 4 6 8 10 100 300 100 200 200 100 b) The cut-out speed of the turbine is improved to 9 m/s. Find the new average speed and the average power produced.

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.

The flow rate of air through a through a pipe is 0.02 m5/s. a pitot static tube is placed in the flow. the radius of the pitot static tube is 1 mm. assuming the flow to be steady and the air to be at 300k, calculate the difference in total and static pressure if the diameter of the pipe is: (a) d 0.1 m d 0.05 m (c) d 0.01 m

Which from the following instrument is commonly used to detect the high pitch butzing sound in bearings? [clo4] a)-digital ultrasonic meter b)-infrared camera c)-spectroscopic d)-vibrometer