Allow me to utter the applicable general principles:
1) The linear acceleration vector of a particle can always be de-composed
into tangential (a_t) and centripetal (a_c) components - mutually
perpendicular.
2) Quantitatively, a_t = dv/dt , where v is the particle speed,
and a_c = v^2/R , where R is the instantaneous radius of curvature of the
particle's path.
3) The net force on the particle can also always be de-composed into
tangential F_t and centripetal F_c components.
4) F=ma can thus always be de-composed into:
F_t = mdv/dt , and
F_c = mv^2/R
Remember, dv/dt is here the time rate of change of the particle speed.