# Airfoil: Quiz

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Question 1: Foils of similar function designed with water as the working fluid are called ________.
Commuter railHydrofoilTramTrolleybus

Question 2: A trailing edge flap acts similar to an aileron, with the difference that it can be retracted partially into the wing if not used (and some flaps even make the plane a ________ if used).
Interplane strutBiplaneJunkers J 1Cabane strut

Question 3: Asymmetric airfoils can generate lift at zero angle of attack, while a symmetric airfoil may better suit frequent inverted flight as in an ________ aeroplane.
AerobaticsRed ArrowsBlack Cats (Royal Navy)Snowbirds

Question 4: The drop in lift can be explained by the action of the upper-surface ________, which separates and greatly thickens over the upper surface at and past the stall angle.
Navier–Stokes equationsDrag (physics)Fluid mechanicsBoundary layer

Question 5: An airfoil (in ________) or aerofoil (in British English) is the shape of a wing or blade (of a propeller, rotor or turbine) or sail as seen in cross-section.
AlaskaUnited StatesAmerican EnglishEnglish language

Question 6: Airfoil design is a major facet of ________.
Bernoulli's principleNavier–Stokes equationsFluid dynamicsAerodynamics

Question 7: ________ airfoils have a characteristic shape with a rounded leading edge, followed by a sharp trailing edge, often with asymmetric camber.
Navier–Stokes equationsAerodynamicsFluid dynamicsBernoulli's principle

Question 8: Analysing the ________ in the linear regime shows that a negative pressure gradient along the flow has the same effect as reducing the speed.
Fluid mechanicsFluid dynamicsNavier–Stokes equationsViscosity

Question 9: The lift force can also be related directly to the average top/bottom velocity difference, without invoking the pressure, by using the concept of circulation and the ________.
Joukowsky transformLift (force)AirfoilKutta–Joukowski theorem

Question 10: In the region of the ________ and near a wingtip a symmetric airfoil can be used to increase the range of angles of attack to avoid spin-stall.
Flap (aircraft)AileronAircraft flight control systemElevator (aircraft)