The concept of the 5th law was referred to by newton in his 3rd law:

*"if the bodies are not hindered by any other impediments."*

The topic of the 5th law is what defines this "impediment."

The topic of the 5th law is that momentum is only transfered while force is applied. Repulsion or resistance is defined as that which allows one body to transfer more momentum to another body than would otherwise be possible given their masses and velocities. We can term this law "resistance" or "Force Series" or "force transfer series" or "Repulsion" or "momentum transfer" or even "Aether". While a force is being applied to a body, that body undergoes a change in momentum; namely velocity (or mass) is transferred from one body to another. Total momentum (mass times velocity) is conserved as we already know however the force only exists for the time that the bodies are in force contact (contact in which a force pair exists). The very instant the impacted body is moving the same speed as the impacting body the impacting body cannot exert any more force. In order for all of the impacting bodies momentum to be transfered it would have to impact a body that has infinite mass. The more massive the second body is relative to the first, the more force*time exists and therefore more momentum can be transfered to it. Also the greater the impacting bodies velocity is relative to the impacted body, the more force*time exists and therefore the more momentum can be transfered to it. So the ratio of masses and velocities should be included in an equation and the factor which allows more momentum transfer than only the masses and velocities alone will be termed "resistance". In order to transfer all of a system's momentum to another system there needs to be either an infinite mass of the impacted body or an infinite series of simultaneous forces (momentum transfers). The net effect of this infinite series of force transfers is impulse and this will be proportional (or inversely proportional) to how much time the force pair or force transfer exists and the magnitude of the force. The time they are in contact will be proportional to a factor called resistance and the force applied and the velocities and masses. Therefore the greater the resistance in a given contact, the greater the contact can effect impulse. It may be thought of as denoting how "full" space is locally or how much interaction the system has with the aether. Here is an equation:

Ft=impulse

impulse=mv

mv=Ft.

t=resistance*force

F*F*Resistance=mv

or even just

resistance=impulse/F

We can think of momentum like voltage and force like current. Change in voltage over resistance is current and change in momentum over resistance is force. Time is proportional to resistance.

or

resistance=deltaforce/momentum

"Resistance" is proportional to the time the contact occurs for. Force is going to be involved as well, the materials resistance will likely be a function of the force applied.

The units of resistance are likely seconds cubed divided by kg meter but may differ depending how many other factors besides force are taken into account in it. Resistance can also be coined the "NatureSlacker coefficient" or the "Momentum transfer coefficient"

This means given a force and a highly repulsive contact you can generate a higher momentum change or impulse.

An example of this is pushing a boulder. Not only does your hand need to push the boulder but so does your arm, your torso, your leg, your foot, and the earth etc etc. Another example is a bullet leaving a gun. The gas molecule pushing the bullet needs to push on the gas molecule behind it, and that one on the one behind it, etc etc, and that molecule on the gun, and the gun on the hand, etc etc.

The conclusion of this law is that since force can be applied for non zero time we know that repulsive forces exist throughout the universe and therefore the universe is a closed system. Occams razor gives us the conclusion that the universe or systems of universes are infinite in all directions and are "full". There is no void into infinity.

impetus or impulse discovered

https://www.physicsforums.com/threads/momentum-and-impulse-help-please.282894/

Tesla may describe repulsion with the term "Aether".

http://aetherforce.com/the-defiance-of-nikola-tesla/

Aristotle described the "unmoved mover" which would be a solution to this paradox.

https://en.m.wikipedia.org/wiki/Unmoved_mover