“An aircraft flying at an altitude where the air density is 0.00238 $\frac{\text{slug}}{\text{ft³}}$ has a wing area of 280 ft² and a lift coefficient (C_L) of 0.45. What is the lift force (lb) when the aircraft speed is 200 ft/s?”

The lift equation for an aircraft is:

$L=0.5\times \rho \times V^2\times S\times C_L$

• L = lift (lb_f)
• ρ = air density (slug/ft³)
• V = velocity (ft/s)
• S = wing area (ft²)
• C_L = lift coefficient (dimensionless)

Now plug in: L = 0.5 × (0.00238 slug/ft³) × (200 fps)² × (280 ft²) × (0.45) = 6,006 lb

Therefore, the lift force is ~6,000 lbs.