Question

how can you say that a body is in motion? is it a common property?

Answer 1

An Object is said to be in rest if its changes its position with respect to surroundings[observer] and time.
Motion and rest are two relative terms.
It is the common property.

For example:
 A car moving on a road.
Car is changing its position with respect to surroundings like trees on the road and other vehicles passing by.
With respect to seat , passenger in car , the driver is at rest.

Answer 2

Answer:

Explanation:

An object is said to be in motion if it changes it's surrounding with respect to time.Example-a plane flying in the sky .