State of Rest and Motion
In physics, the objects which do not change their position are said to be at rest, while those which change their position are said to be in motion. Example: A book lying on a table, the walls of a room (at rest) Cars and buses running on the road, birds and aeroplanes ying in air (in motion). Motion is a relative phenomenon. is means that an object appearing to be in motion to one person can appear to be at rest as viewed by another person. For example, trees on roadside would appear to move backward for a person travelling in a car while the same tree would appear to be at rest for a person standing on road side.