3 Fig. 3.1 shows a model of a wind turbine used to demonstrate the use of wind energy to generate
electricity. The wind is blowing towards the model, as shown.
turbine blades
circular area swept out
by turbine blades
wind
Fig. 3.1
(a) The mass of air passing through the circular area swept out by the turbine blades each
second is 7.5kg. The kinetic energy of the air that passes through this circular area cach
second is 240J.
() Calculate the speed of the alr.
spoed
131
(11) The kinetic energy of the air drives a generator. State the input power of the air passing
through the turbine blades.