A horizontal disc of radius R rotates with a constant angular velocity about a stationary vertical axis

Question:

A horizontal disc of radius R rotates with a constant angular velocity ω about a stationary vertical axis passing through its edge. Along the circumference of the disc a particle of mass m moves with a velocity that is constant relative to the disc. At the moment when the particle is at the maximum distance from the rotation axis, the resultant of the inertial forces Fin acting on the particle in the reference frame fixed to the disc turns into zero. Find:
(a) The acceleration ω' of the particle relative to the disc;
(b) The dependence of Fin on the distance from the rotation axis