movement
a continuous change in position is called Motion
movement
The change in an objects position is called motion.
A person walking is an example of a change in position over time.
velocity
The answer is displacement.
Changes in position over time is motion, and the rate of change may be velocity or speed.
Speed --- actually, if your question is 'position' over time, there is no answer since position is a vector quantity. And position divided by time will still yield a vector quantity-- velocity. If the question asks for change in distance over time, then the answer is speed. --gh ---
movement
Velocity is the rate of change of position over time.
In the question, "an object's change in position...over...time" is a perfectly reasonable definition of velocity.
A change in position in a certain amount of time is called motion.