A one-fourth scale model of an airplane is to be tested in water. The airplane has a velocity of 700 km/h in air at −50°C. The water temperature in the test section is 10°C.

In order to achieve similarity between the model and the prototype, the test is done at a water velocity of 393 km/h.

The properties of air at 1 atm and –50°C: ρ = 1.582 kg/m³, μ = 1.474 × 10^–5 kg/m·s.

The properties of water at 1 atm and 10°C: ρ = 999.7 kg/m³, μ = 1.307 × 10^–3 kg/m·s.

If the average drag force on the model is measured to be 13,800 N, the drag force on the prototype is

(a) 590 N 

(b) 862 N 

(c) 1109 N 

(d) 4655 N

(e) 3450 N