you know that modeling is an initial and basic approach in all science disciplines..
without this you cant solve any problem.. physics and physic eqautions are also dervied and obtained in the same way..
f=m*a equation is a universally accepted equation .. I just gave an example using that equation and assuming the car is accelerating at 9 secs..
you can broaden the example with different acceleration and mass values .. but the difference will never be 1 secs nor 0
For goodness sakes Cem.
I have accepted that the formula is creditable. It works in a sterile environment. It doesn't take into consideration tyre friction (increased as mass is added (and you know more than Mr Goodyear about tyres)), Drag Co efficient (the chassis moves out of 'perfect' when weight is added), Torque (your simple equation doesn't involve torque).
Your equation is useless in the real world. I'll say that a million times, but you still won't accept the truth.