Rotational Drag is similar to the Drag behavior, except that it affects Rotation instead of position. Rotational Drag simulates friction affecting objects that are spinning due to keyframed or behavior-driven changes to the Rotation parameter. By setting higher Drag values, you can slow rotational changes to an eventual stop.
Adjust this behavior using the controls in the Behaviors Inspector:
Affect Subobjects: A checkbox that appears when this behavior is applied to an object that contains multiple objects, such as a group, a particle emitter, a replicator, or a text layer. When this checkbox is selected, all objects enclosed in the parent object are affected individually. When this checkbox is deselected, all objects enclosed in the parent object are affected by the behavior together.
Amount: A slider used to slow down an object’s rotation over time, causing it to eventually come to a stop. Higher Amount values result in the rotation ending sooner.