If coefficient of lift Cl is doubled while other variables remain constant, lift will:

• A. Remain the same
• B. Double
• C. Quadruple
• D. Half

Answer: (B)

Lift is proportional to the lift coefficient Cl when speed, air density, and wing area are fixed. The lift equation is L = Cl × q × S, where q is dynamic pressure (q = 0.5 × ρ × V²) and S is wing area. If Cl is doubled while ρ, V, and S stay the same, L doubles because you’re multiplying the same dynamic pressure and area by a coefficient that is twice as large. In other words, the wing becomes twice as effective at generating lift at that operating condition, assuming you don’t push the wing into stall or change other conditions.