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;