9 (a) The diagram shows a vertical wind turbine with blades 30 m long. The blades are stationary with the point A being the maximum distance possible from the horizontal ground. The point B is such that the angle of elevation of A from B is 34° and the angle of elevation of the centre of the blades, C, from B is 25°. Calculate the distance AB. (b) A different wind turbine, shown in the diagram on the next page, has the centre of its blades, F, 75 m from the base of the turbine, D. Point E is on sloping ground, 180 m from F and 130 m from D. Calculate the angle of depression of E from F. (c) P is the point on a blade which is furthest from the centre of the blades. Each blade is 30 m long. (i) Calculate the distance travelled by P as the blade completes one revolution. (ii) The blade completes 15 revolutions per minute. Calculate the speed of P, giving your answer in kilometres per hour. (iii) A point Q lies on the straight line between P and the centre of the blades. Q travels 90 m as the blade completes one revolution. Calculate PQ.