Later, momentum was considered to be conserved. So the historical basis for the definition of energy contradicts modern concepts. It also contradicts the logic of Newton's laws which indicate that the force-time combination must be conserved through all interactions, because otherwise forces would not be equal and opposite. Force times time produces a defined amount of mv, not mv . Newton then extended the concept stating three important laws.
Force equals mass times acceleration.
For every force, there must be an equal and opposite force. An object at rest stays at rest, or an object in motion maintains its motion unless a force acts upon it. Eventually, Leibniz's view became the concept of kinetic energy in spite of contradictions with Newton's laws. The issue was how to relate force to motion in order to get a quantity which is conserved. While force creates motion, one additional factor must be known to quantitate the results.