Final answer:
If a seesaw rotates in a clockwise direction, the angular acceleration's sign is negative following the conventional right-hand rule where counterclockwise rotation is positive and the angular velocity points in the positive z-direction.
Step-by-step explanation:
When considering the rotation of a seesaw, we can analyze the situation using Newton's laws of motion and the rules of rotational motion. If the seesaw rotates in a clockwise direction, this indicates that the torque on the right side is greater than the torque on the left side. The sign of the angular acceleration will be negative if we are assuming the standard convention where counterclockwise rotation is considered positive.
For counterclockwise rotation in the coordinate system shown in your studies, the angular velocity points in the positive z-direction by the right-hand rule. This rule states that if you curl the fingers of your right hand in the direction of rotation, your thumb will point in the direction of the angular velocity vector. Thus, for clockwise rotation, your thumb would point in the negative z-direction.