  In this paper, we introduce a new class of curves \alpha called a
f-rectifying curves, which its f-position vector defined by
{\alpha}_{f}(s)=\int f(s)T(s)ds always lie in the rectifying plane of \alpha,
where f is an integrable function and T is the speed curve of {\alpha}. In
particular case, when the function f=0 or constant, the class of f-rectifying
curves are helix or rectifying curves, respectively. The classification and the
characterization of such curves in terms of their curvature and the torsion
functions are given with a physical interpretation. We close this study with
some examples.
