Question

Why motion and rest are relative?

Answer 1

These are known as relative concepts because both need some kind of point of comparison.

Explanation:

For example, right now I think I'm at rest typing this answer on my computer, but compared to someone looking at the earth from space, I'm actually rotating around an axis pretty quickly....and circling the sun, etc.

Then, imagine driving a car down a road while you're drinking a soda. To you, the soda is not moving, but to someone watching you from the side of the road, the soda is moving at the same speed as the car