An object is in motion when its distance from another object is changing. ... A reference point is a place or object used for comparison to determine if something is in motion. An object is in motion if it changes position relative to a reference point. You assume that the reference point is stationary, or not moving.
A object is in motion when its distance from another object it changing.
a reference point is a place or object used for comparison to determine if something is in motion. You can assume that the refrence point is stuck or not moving.
