Rest and motion are two fundamental concepts in the study of mechanics. They are relative terms, meaning their meaning depends on the frame of reference from which they are observed.
- Rest refers to the state of an object when it does not change its position with respect to its surroundings over time. In simpler terms, if an object is not moving, it is said to be at rest.
- Motion refers to the change in the position of an object with respect to time. If an object is changing its position relative to some reference point, it is in motion.
For example, if a person is sitting in a car at a traffic light, from the perspective of the person sitting inside, the car is at rest. However, from the perspective of someone standing outside the car, the car is in motion as it is stationary but can be considered part of the moving traffic.
Thus, rest and motion are relative to the observer’s frame of reference. An object may appear to be in rest in one frame of reference and in motion in another.