Explanation:
A body is said to be at rest if doesn't change it's position with respect to its surroundings while a body is said to be in motion if it continuously changes it's position with respect to its surroundings.
Motion : If an object change its position with respect to time and surroundings, it is said to be in motion .
For example: If we stand on a road and observe a moving car , we will findo that it's position is continuously changing with respect to us and different time intervals . So the car is in motion
Rest: We can say that a body is at rest , if it does not change its position with respect to time and it's surroundings .
For example: a standing tree remain fixed in its place if you see it at different times intervals . So , it is said to be in the state of rest.
Rest and motion are relative terms : when we say that a body is at rest , first we consider that the earth is at rest . But, actually the earth itself is constantly rotating on it's own axis . So ,everything on the earth is also in motion.
