For a given wing area, the lift of an aeroplane is proportional to the square of its speed. The table shows the lift of a Boeing 747 jet airline at various speeds.
(i) Is the pattern of lifts quadratic? Give a reason for your answer.
(ii) Copy the grid provided and draw the graph to show how the lift increases with speed.
(iii) An airplane requires a lift of 350 000 Newtons at take-off . Using the graph, estimate the minimum speed the plane must travel at, to get enough lift to take fl ight.
(iv) Give a reason why you think that bigger planes need longer runways.
(b) Daisy is travelling to Denmark. She has €1 500.
(i) How many Danish krone will she receive if the exchange rate is €1 = Kr7 ⋅ 44? The foreign exchange offi ce charges Daisy 2 ⋅ 5% commission on the transaction. (ii) What is the fi nal amount of krone Daisy will receive after paying this charge?
(c) When Daisy lands in Denmark, she sees the Danish fl ag at the airport, as shown. ● ●
The fl ag measures 3 m by 2 m. Let x be the width of the stripes.
(i) What is the total area of the fl ag? (ii) What is the total area of the white cross in terms of x ? (iii) What is the area of the red portion of the fl ag?
(iv) If the area of the white cross is equal to one-third of the area of the red portion, using your answers to (ii) and (iii) form an equation in terms of x .
(v) Solve this equation to fi nd the width of the white cross. Give your answer to two decimal places.