The wheels on a moving bicycle have both translational (or linear) and rotational motions. What is meant by the phrase "a rigid body, such as a bicycle wheel, is in equilibrium"?
(a) The body cannot have translational or rotational motion of any kind.
(b) The body can have translational motion, but it cannot have rotational motion.
(c) The body cannot have translational motion, but it can have rotational motion.
(d) The body can have translational and rotational motions, as long as its translational acceleration and angular acceleration are zero.