function F = F_total(A, v, c_D, m, alpha)
%   F_TOTAL Frontal Surface Area, velocity, Coefficient of
%   Drag, mass, Angle of surface (road)
%   F_TOTAL(A, V, C_D, M, ALPHA) computes the total force
%   required to move a vehicle (including its rider) of
%   mass M in kilograms, travelling at velocity V in
%   meters per second, having a total frontal surface area
%   of A in square meters, having a coefficient of drag
%   C_D, and travelling on a level or inclined surface
%   at angle ALPHA in degrees.
%   The total force takes into account the Aerodynamic
%   drag, the rolling resistance, as well as the force
%   required to move on an inclined surface.

error(nargchk(4, 5, nargin));

if nargin == 4
  alpha = 0;
end

F = F_air(A, v, c_D) + F_roll(m, v) + F_slope(alpha, m);