1609 m/mile A speed of 90 MPH corresponds to 90 * ------------ = 40.2 meters/second 3600 s/hour 2 drag force = - 0.5 * Cd * density * area * velocity 2 = - 0.5 * (0.40) * (1.23 kg/m^3) * (4.26E-3 m^2) * (40.2 m/s) = - 1.69 Newtons That means 1.69 Newtons in the direction opposite to the current velocity. This drag force is larger than the 1.42 Newtons of gravitational force.