Chapter 3 A Four forces Lift Ground effect

The four forces acting on an airplane in flight are

• A – lift, weight, thrust, and drag.
• B – lift, weight, gravity, and thrust.
• C – lift, gravity, power, and friction.

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

• A – During unaccelerated flight.
• B – When the aircraft is accelerating.
• C – When the aircraft is at rest on the ground.

Tags

NGSS.HS-PS2-1

(Refer to Figure 1.) The acute angle A is the angle of

• A – incidence.

• B – attack.

• C – dihedral.

The term “angle of attack” is defined as the angle between the

• A – chord line of the wing and the relative wind.
• B – airplane’s longitudinal axis and that of the air striking the airfoil.
• C – airplane’s center line and the relative wind.

The angle between the chord line of an airfoil and the relative wind is known as the angle of

• A – lift.
• B – attack.
• C – incidence.

What is the relationship of lift, drag, thrust, and weight when the airplane is in straight-and-level flight?

• A – Lift, drag, and weight equal thrust.
• B – Lift and weight equal thrust and drag.
• C – Lift equals weight and thrust equals drag.

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

• A – decrease the angle of descent without increasing the airspeed.
• B – enable a touchdown at a higher indicated airspeed.
• C – increase the angle of descent without increasing the airspeed.

What is one purpose of wing flaps?

• A – To decrease wing area to vary the lift.
• B – To relieve the pilot of maintaining continuous pressure on the controls.
• C – To enable the pilot to make steeper approaches to a landing without increasing the airspeed.

Tags

NGSS.MS-PS2-1

The angle of attack at which an airplane wing stalls

• A – increases if the CG is moved forward.
• B – changes with an increase in gross weight.
• C – remains the same regardless of gross weight.

What is ground effect?

• A – The result of the interference of the surface of the Earth with the airflow patterns about an airplane.
• B – The result of an alteration in airflow patterns increasing induced drag about the wings of an airplane.
• C – The result of the disruption of the airflow patterns about the wings of an airplane to the point where the wings can no longer support the airplane in flight.