There are 3 laws of motion
law 1 a body continues to be in motion or rest unless acted upon by an external object or force
law 2the rate of change of momentum of an object is proportional to net force applied on object
law 3 every action has an equal and opposite reaction

newtons 1st law states that a body continues in its state of interval or in uniform motion in a straight forward line unless external force act on it .
newton's 2nd law states that the amount of change in momentum of a body is directly proportional to applied force and takes place in the path of in which force acts .
newton's 3rd law states that to every action there is equal and opposite reaction reversed or opposite reaction .
Law of inertia state that a body continues to be in a state of rest or of uniform motion unless the external force is applied on the body. The acceleration of body directly proportional to force and inversely proportional to mass. Discuss the action- reaction law. and you can watch this video it is explained with simple examples....