Rest and Motion
In our daily life we come across a variety of objects. Some of them like buildings, tables, chairs, plants etc are stationary i.e. they do not change their position from one place to another. Also, there are other objects like moving cars, running trains etc which change their positions from one place to another.
When a body does not change its position from one place to another with respect to another body present in its surroundings i.e. the reference body, the body is said to be at rest.
When a body changes its position from one place to another with respect to another body in it’s surroundings i.e. the reference body, the body is said to be in motion.
It should be known that rest and motion is always a relative term. They depend upon the position of an observer. For example, to a person sitting inside a moving train, everything inside the train appears to be at rest, while the trees, buildings, fields etc outside the train appear to be running past the train i opposite direction i.e. they appear to be in motion.
Again, to a person standing outside the train, the trees, buildings, fields etc outside the train appear to be at rest, while everything inside the train appear to be in motion. So, rest and motion are always relative terms.
