The 0.5-lb ball is guided along the vertical circular path = 2r, cos 8 using the arm OA. If the arm has an angular velocity 80.4 rad/s and an angular acceleration 0.8 rad/s² at the instant = 30°,determine the force of the arm on the ball. Neglect friction and the size of the ball. Set r= 0.4 ft.

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