Which is at rest and which is in motion?

Imagine that you are on a boat and filming another boat that is next to you.

Suppose you have shot a video as the one shown below. 

Play the video and observe.

                                                                               Video 2.3 (a): Riddle 3

1. Could you say if both these boats were moving or not?
 
2. Why is it difficult to say if these boats are in motion?
 

In 2.2 you have discussed the importance of position and time to help you describe the motion of any object.

Could you say if the knowledge of their ‘position’ and ‘time’ would help to state the motion of these two boats?

After Discussing the questions please watch the following video and discuss the questions given below the video.
 

How could you sense now if the boat was moving ? Use position and time to describe the motion of this boat.

If two objects move at the same speed in the same direction, then you cannot say if they are in motion or are at rest.

You feel something is in motion if it changes its speed, or position with respect to you or with respect to some other object in your view. 

We do not sense the motion of the earth because we are moving with it at the same speed in the same direction.