Step 1 - FBD: Draw a free body diagram of the bar.
Step 2 - Kinetics: Write down the Newton/Euler equations for the sphere. Since there is no fixed point on the bar, choose the center of mass for your moment equation
Step 3 - Use the rigid body kinematics equation for relating the accelerations of points A and B on the bar:
aB = aA + α x rB/A - ω2 rB/A
followed by relating the acceleration of B to the acceleration of the bar's center of mass, G:
aG = aB + α x rG/B - ω2 rG/B
Step 4 - Solve