function F = F_air(A, v, c_D)
% F_AIR Frontal Surface Area, velocity, Coefficient of Drag
% F_AIR(A, V, C_D) computes the force required to move a
% vehicle (including its rider), being the inverse of the
% aerodynamic drag, given the frontal surface area A in
% square meters, the velocity V in meters per second at
% which the vehicle is travelling, and the coefficient of
% drag C_D, which describes the shape of the vehicle.
error(nargchk(3, 3, nargin));
rho = 1.225;
F = 0.5 * rho * A * (v^2) * c_D;