Lift, Drag, and the Angle of AttackAircraft & Engines — DGCA CPL practice questions
Question 1 of 5
In the lift formula L = Cʟ × ½ρv² × S, the term ½ρv² represents:
All 5 questions — Lift, Drag, and the Angle of Attack
Aircraft & Engines · DGCA CPL. The correct option is marked on each.
Q1. In the lift formula L = Cʟ × ½ρv² × S, the term ½ρv² represents:
- A.Static pressure
- B.Dynamic pressure✓
- C.Total pressure
- D.Wing loading
Why: ½ρv² is dynamic pressure; Cʟ accounts for AOA and aerofoil shape, and S is wing area.
Q2. As the angle of attack increases towards the stall, the Centre of Pressure:
- A.Moves aft
- B.Moves forward✓
- C.Stays fixed
- D.Moves to the wingtip
Why: The point of lowest upper-surface pressure moves forward with rising AOA, taking the CP forward — most forward just before the stall.
Q3. If IAS is doubled in level flight, to keep lift constant the coefficient of lift must reduce to:
- A.One half
- B.One quarter✓
- C.Three quarters
- D.It must double
Why: Dynamic pressure varies with v², so doubling IAS quadruples it; Cʟ (via AOA) must fall to a quarter to keep L constant.
Q4. The maximum lift/drag ratio of a typical aerofoil occurs at approximately:
- A.4° AOA✓
- B.8° AOA
- C.12° AOA
- D.16° AOA
Why: L/D max occurs at the optimum AOA of about 4°; flying here gives best glide range and maximum endurance. 16° is the stalling angle.
Q5. The angle of attack for maximum L/D ratio with a change in aircraft weight:
- A.Increases with weight
- B.Decreases with weight
- C.Does not change, but the IAS to achieve it does✓
- D.Changes with altitude only
Why: The optimum AOA is fixed by the aerofoil; a heavier aircraft simply needs a higher IAS to fly at that same AOA.