Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

Consider the following statements regarding the mechanical equilibrium of a rigid body: (A) A rigid body is in complete mechanical equilibrium if both its total linear momentum and total angular momentum do not change with time. (B) If the net external force acting on a rigid body is zero, the total torque on the body is independent of the choice of origin. (C) A couple comprises two equal and opposite forces acting along two distinct, parallel lines of action. (D) A rigid body acted upon solely by an unbalanced couple cannot be in rotational equilibrium. Which of the above statements are correct?

1. (A) and (C) only
2. (A), (B) and (C) only
3. (A), (B), (C) and (D)
4. (B) and (D) only