Acyclist rides over the top of a hill. is the bicycle's motion rotational, translational, or a combination of both? uniform circular motion.

A combination of both.

In fact, if we consider the wheels of the bycicle, they are moving by circular motion (since they cover a circular path), so this motion is rotational because the wheels are turning around an axis. However, the bycicle is moving from a certain point (bottom of the hill) to another location (top of the hill), so it is also a translational motion.