Answer: 0.288
Explanation:
Given
Pressure of the car, P = 1 atm
Temperature of the car, T = 25° C
Speed of the car, v = 90 km/h = 90*1000/3600 = 25 m/s
Height of the car, h = 1.25 m
Width of the car, b = 1.65 m
Force acting on the far, F = 220 N
Drag coefficient, C(d) = ?
Using our table A-9, we can trace that the density of air ρ, at the given temperature and pressure of 25 °C and 1 atm, is 1.184 kg/m³
Area = h *b
Area = 1.25 * 1.65
Area = 2.0625 m²
Now we solve for the drag coefficient using the formula
C(d) = F / (1/2 * ρ * A * v²)
C(d) = 220 / (0.5 * 1.184 * 2.0625 * 25²)
C(d) = 220 / (1.221 * 625)
C(d) = 220 / 763.125
C(d) = 0.288
Therefore, the drag coefficient is 0.288
