a) A plane flies at 870 km/hr into a headwind of 40 km/hr at 450 with the direction ofthe plane as shown.Wind 40km/hr 45" - = = What is the actual speed of the plane as a result of this headwind? Give 3 significant figures. b) A mass is oscillating up and down at the end of a spring whose length L (in centimetres) after time f (in seconds) is modelled by the following function: L(t) = 19 + 10 sin 2Calculate the length of the spring after 9 seconds.c) The diagram shows a circle with centre O and radius 34 cm. A and B are points on the circumference such that the arc AB forms an angle of 100" as shown. O 100 B ACalculate the length of arc AB. Use angle 0 in radians. (Give your answer to 4 significant figures) ii) Find the area of the sector AOB (shaded area). (Give your answer to 6 significant figures)