有向心淨力並不代表物件正處於Cir.Motion??

Without looking at the original sentence, I could only give the following answer.

By circular motion, if you limit yourself to a "perfect circle", then a centripetal force (note that centripetal force must be a net-force) cannot ensure that the object is moving in a circle. An object moves in a circular path when acted by a centripetal force if and only if the speed of the object is constant.

An object could have tangential accleration when there is a tangetnial force acting. Under such acceleration, the resultant motion of the object would not be in a circle.

If that NET force is always tangent to the motion of the object, and it's value is constant, it must be in a circular motion.

其實向心淨力係可以出現唔夠 的情況, 即係個物件會愈轉愈開 ( 但不代表佢冇
向心力) 亦即係個path唔會係圓
不正處於Cir.Motion.