Lesson 7 Pre-Quiz

The four forces acting on an airplane in flight are

• Lift, weight, thrust, and drag.

• Life, weight, gravity, and thrust.

• Lift, gravity, power, and friction.

When are the four forces that act on an airplane in equilibrium?

• During unaccelerated flight.

• When the aircraft is accelerating.

• When the aircraft is at rest on the ground.

Which statement related to Bernoulli's principle?

• For every action there is an equal and opposite reaction.

• An additional upward force is generated as the lower surface of the airfoil deflects air downward.

• Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface.

The term 'angle of attack' is defined as the angle

• Between the wing chord line and the relative wind.

• Between the airplane's climb angle and the horizon.

• Formed by the longitudinal axis of the airplane and the chord line of the wing.

One of the main functions of flaps during approach and landing is to

• Decrease the angle of descent without increasing the airspeed.

• Permit a touchdown at a higher indicated airspeed.

• Increase the angle of descent without increasing the airspeed.

What is ground effect?

• The result of the interference of the surface of the Earth with the airflow patterns about an airplane.

• The result of an alternation in airflow patterns increasing induced drag about the wings of an airplane.

• The result of the disruption of the airflow patterns about the wings of an airplane to the point where the wings will no longer support the airplane in flight.

Floating caused by the phenomenon of ground effect will be most realized during an approach to land when at

• Less than the length of the wingspan above the surface.

• Twice the length of the wingspan above the surface.

• A higher-than-normal angle of attack.