when do you say an object is at rest
Rest (physics) Rest is a state in physics that refers to an object being stationary relative to a particular frame of reference or another object; when the position of a body with respect to its surroundings does not change with time it is said to be "at rest". According to the theory of relativity, it is said that an object is "at rest relative to" another. Two or more than two objects are said to be at rest, if its position with respect to each other is not changing or moving with uniform velocity with respect to each other; rest and motion are relative terms.