NEET Physics Motion in a Straight Line / सरल रेखा में गति Notes - Rest and Motion            

Rest and Motion            

If a body does not change its position as time passes with respect to frame of reference, it is said to be at rest.             And if a body changes its position as time passes with respect to frame of reference, it is said to be in motion. Frame of Reference: It is a system to which a set of coordinates are attached and with reference to which observer describes any event. A passenger standing on platform observes that tree on a platform is at rest. But when the same passenger is passing away in a train through station, observes that tree is in motion. In both conditions observer is right. But observations are different because in first situation observer stands on a platform, which is reference frame at rest and in second situation observer moving in train, which is reference frame in motion. So rest and motion are relative terms. It depends upon the frame of references.