Objects with a net centripetal force travel in circular motion.
Riding on a merry-go-round (A . . . moving around in a complete circle),
and Swinging on a playground swing (C . . . moving back and forth in a
part of a circle) are both examples of circular motion.
Sliding down a playground slide and Climbing up a climbing wall
are both straight-line motion. The paths aren't parts of circles.
