The quarter-circular slotted arm oa is rotating about a horizontal axis through point o with a constant counterclockwise angular velocity ω = 6.4 rad /sec. the 0.13-lb particle p is epoxied to the arm at the position β = 69°. determine the magnitued of the tangential force f parallel to the slot which the epoxy must support so that the particle does not move along the slot. the value of r = 1.6 ft.