Newton made the applied force calculation very clumsy and complicated. Any description of science would be as such that everybody understand the phenomena and can relate day to day activities. To calculate the value of applied force Newton introduced momentum, inertia, impulse, acceleration etc. Still we unable to answer what the relation is between applied force & momentum, applied force & inertia, applied force & impulse. Still we are in an ignorance why do we use a ratio say acceleration and why do we not use another ratio say velocity (as velocity first then acceleration) to quantify the value of applied force. What happens actually when you apply a force on an object? Applied force either moves an object or increases/decreases the velocity of an object. It might change the mass of the nucleus (as mass & energy can change each other) or might change the energy level of the electrons of outer shells. We can relate the increase or decrease of energy into the outer shells of electrons with acceleration or deceleration. If applied force transforms into energy and that increases the energy level, it creates acceleration and vice versa. If the transformation of the energy gets arrested into the object and if it doesn’t change with time/distance, the object will move with uniform velocity. So, applied force acts as an operating force.
We can very well explain the phenomena by “cause & effect”. If an object moves/accelerates due to an applied force then obviously the object will move so long the value of applied force act on it and an external force (say, friction) reduces (in some cases increases) the value of applied force. According to Newton, calculated value of applied force on an object, moving with uniform velocity, is zero. According to the principle of “cause & effect” it can’t be happened, because uniform velocity couldn’t be the primordial stage of an object as it was created by a so called big bang a big thrust.
According to Newton, acceleration occurs due to an applied force. Here a question arises, how come an object gets a momentum? Somebody may answer “an impulse”. Here another question arises, impulse isn’t it an applied force? Somebody might argue, impulse creates a momentum and applied force creates acceleration. Here we get puzzled to define applied force which remains far from the natural phenomena. Here a natural phenomenon doesn’t explain the principle of sciences rather a principle of science directs/explains the natural phenomena. That’s why the science, now a day has become so complicated.
According to Newton, inertia is an inbuilt quality of an object. Due to inertia, an object tries to preserve its own state. We are still in misconception and we don’t know why inertia actually evolves/prevails. In my consideration, inertia evolves/prevails only when there is an arena of gravitational force. In a real vacuum where the values of all integers are zero, objects do not move anywhere, wherever in vacuum if you place an object that doesn’t move. If you place an object/marble on a paper on the top of a glass and due to the sudden taking away of the paper, the object/marble does not fall into the glass in vacuum. Whereas if the experiment is conducted in a gravitational field, the object/marble falls into the glass.
In case of the inertia of motion, when you apply a sudden force on a static object or a sudden brake on a moving object, that shows an abnormal behavior due to the presence of gravitational field. Whereas if you do the same experiment in a true vacuum you finds a normal behavior. In a true vacuum, if one marble hits another marble (static), both the interacting marbles move conjunctly with same velocity in accordance with mechanics for new age. In this case, static object/marble will not hindrance the movement of the moving object or resist/oppose the hit/applied force on it.