A reference point must be chosen to determine the motion of an object.
A Reference Point A reference point is needed to determine if an object is in motion.
A Reference Point A reference point is needed to determine if an object is in motion.
To support you in specifying how the reference point is placed and how the object is moved away from the reference point.
when the object is at rest
motion
To help you state how the reference point placement is and how the object is moved from the reference point
A Reference Point A reference point is needed to determine if an object is in motion.
A Reference Point A reference point is needed to determine if an object is in motion.
A Reference Point A reference point is needed to determine if an object is in motion.
A Reference Point A reference point is needed to determine if an object is in motion.
Relative to any chosen reference point.
A reference point
reference point
To support you in specifying how the reference point is placed and how the object is moved away from the reference point.
That would be a reference point.
A landmark - or reference point.
when the object is at rest