16. An offshore oil well springs a leak and oil is spilling into the ocean, in an outward circular shape. Every time the diameter of the circle of oil increases by half a kilometre, the diameter is recorded, along with the time, in days, since the leak began. The recorded values are shown in the table below.
Diameter (km) 0 0⋅5 1⋅0 1⋅5 2⋅0 2⋅5 3⋅0 3⋅5 4⋅0 4⋅5 No. of days
(i) Identify the type of pattern formed by the number of days.
(ii) Draw a graph of the data in the table, putting the diameters on the x-axis and describe the graph.
(iii) Find a general expression Tn of days.
for this pattern of the number 5⋅0 0 1⋅5 6⋅0 13⋅5 24⋅0 37⋅5 54⋅0 73⋅5 96⋅0 121⋅5 150⋅0
17. For a given wing area, the lift of an aeroplane (or a bird) is proportional to the square of its speed. The table shows the lifts for an aeroplane at various speeds.