My apologies in advance for so rookie question.
Stage:
An object (hereinafter A) traveling through space (suppose no pollutant forces) at a constant velocity wrecks against another object (hereinafter B) at rest.
Considerations:
A is going to lose velocity, therefore a negative acceleration has been applied on it.
B is going to acquire velocity, therefore a acceleration has been applied on it.
As an acceleration has been applied on both objects, I affirm that a force has been applied on them.
Question:
What and how does the velocity of object A transform into a force when impacting?
I have not seen any magnitude which has ML/T dimension which can explain me this event.
( I suppose there is not one force before impact because A has no acceleration )
Thank you.
Best Answer
According to Newton, the fundamental quantity of motion is momentum, and force changes momentum. The idea of acceleration and its relationship to force comes from change in momentum.
Both of your objects have an initial momentum, $mv$, with units $$kg\frac{m}{s}.$$ and that is the ML/T magnitude you seek.
During the time of the collision, the rate of change of momentum of each object has units $$\frac{kg\frac{m}{s}}{s}.$$ This rate of change is proportional to the force, and is equal to $ma$
If your question also pertains to how force arises physically from the collision of two objects with velocities, just remember that contact forces are electrostatic in nature. So the objects get compressed against the forces of electrostatic repulsion, and the kinetic energy they had is divided between temporary storage in the fields between electrons during elastic deformation, and transfer to thermal energy during permanent deformation.