Distance and Time 

Look at the video below to tell whether motion is easy to describe this time?

Video 2.5

Why is it easy to describe the motion of objects in these video clips?

Let us guess the strategy that you used to describe this motion.

You used the static background to describe the motion of the boat. The boat changes its position from one point to another which means it covers some distance. You also intuitively know that it takes time for the boat to move from one point to another.
 
To describe the motion of an object you need both  - the distance covered by the object and the time taken to cover this distance.