The BodyAngularVelocity object allows angular force on any part or object, giving you the ability to rotate an object or group in a specific direction. The force that is put on this object does not have a goal, meaning it will constantly apply the same force.
The AngularVelocity property of the class controls the rotation of the object. Its direction is the axis which the part rotates around, and the magnitude is the speed in radians. For example, an AngularVelocity of Vector3.new(0, 1, 0)* math.rad(360) makes the part rotate around the Y axis once per second.