A body will continue in its state of rest or uniform motion in a straight line, unless acted by some external force. What does this statement represent?
Newton's first law of motion
Newton’s First Law of motion states that a body at rest will remain at rest and body at motion will remain in uniform motion unless an unbalanced force acts on it to change its state of rest or of uniform motion. Therefore if no external force is acting on a body, a body will either remain in state of rest or uniform motion.