A 0.5-kg block B slides without friction inside a slot cut in arm OA which rotates in a ve...

A 0.5-kg block B slides without friction inside a slot cut in arm OA which rotates in a vertical plane. The motion of the rod is defined by the relation  = 10 rad/s2, constant. At the instant when θ = 45°, r = 0.8 m and the velocity of the block is zero. Determine at this instant, (a) the force exerted on the block by the arm, (b) the relative acceleration of the Muck with respect to the arm.

Fig. P12.67