Explanation:
Motion and rest are two different states of an object. By state of object I don’t mean its state relating to density, i.e., solid, liquid or gas, but the state relating to its position.
If it is put simply, an object that changes its position is said to be in motion. The opposite is rest.
However, perspective plays a huge role in it. Nuclear atoms are always in motion but when we see an object in the macro world or through our naked eyes, it seems to be at rest. Or if you consider Earth, we are always moving around while spinning, and still we can be at rest at times and in motion at times. So, motion and rest are relative to a closed frame.
Considering the closed frame, an object is said to be at rest if it doesn’t change its position at any given time. And, motion is when an object changes its position with respect to time within the closed frame. The state of motion is then subjected to uniform or non-uniform as per the scale of change in position with respect to time. If the scale is uniform at any given time is same then it is uniform motion, else it is non-uniform.
Physics is a little confusing as you gain knowledge. However, the fundamentals can make you quite adept at understanding them.