When a rigid body is undergoing purely translational motion, which of the following statements are true? (Select all that apply) When a rigid body is undergoing purely translational motion, which of the following statements are true? (Select all that apply) The acceleration of the body is different at different points on the body. External forces acting on the body do not affect its translational motion. The sum of external forces equals the mass of the body times the acceleration of the center of mass. The body's motion can be described by the motion of its center of mass alone. Rotational forces play a significant role in the translation of the body