[darcane]

Originally Posted by HypermilerAX

Fr = Cr*m*g
Fa = 0,5*rho*CdA*v²
Fg = m*9,81*sin(atan(slope/100)) (slope in %)

P = (Fr+Fa+Fg)*v

Of course, figuring out Cr, Cd, and A are not simple feats...