Newton's first law of motion states that a body at rest will remain at rest,and a body in motion will continue in motion in a straight line with a uniform speed unless it is compelled by an external force to change its state of rest or of uniform motion.For example,a book lying on a table remains on the table unless we lift it with the force of our hands.And on a frictionless surface, a moving car continues to be in the state of motion until are applied on it.