Drag force proportional to speed squared

Steps:

• Rearrange the equation: F = (1/2) C_d ρ v² A.
• C_d is dimensionless and constant for shape comparison.
• For fixed ρ and A, F ∝ v².
• Thus, the exponent n in F ∝ v^n is 2.

Why B is correct:

• The formula shows drag F scales with v², matching the quadratic dependence in aerodynamics.

Why the others are wrong:

• A: Linear dependence (v^1) applies to low-speed viscous drag, not high-speed form drag on cars.
• C: Cubic (v^3) does not appear in standard drag equations.
• D: Quartic (v^4) is unrelated to drag force scaling.

Final answer: B