Fourth Law of Motion

Newton's first law of motion states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. The key point here is that if there is no net force acting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity. If that velocity is zero, then the object remains at rest. If an external force is applied, the velocity will change because of the force.



Newton's second law of motion explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum (mass times velocity) per change in time. For an object with a constant mass m, the second law states that the force F is the product of an object's mass and its acceleration a:
F = m × a


Newton's third law of motion states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal force on object A. Notice that the forces are exerted on different objects.



Duky’s fourth law of motion states that every object will starts from rest and at last stops at rest or in other words the sum of initial velocities of the object is equal to the sum of final velocities of the object.
Sum of initial velocities = sum of final velocities

It also explain us that bullet fires from the gun is starts from rest not from maximum velocity, it looks that bullet starts from maximum velocity and slowly-slowly velocity goes down because bullet achieve its maximum speed in very short interval of time.

This law also unlock the mystery of the Universe that how Universe form in past & how it comes to an end in future.