If an inelastic collision occurred, some of the energy would be converted to heat, either as a net reduction in mv or a reduction in momentum relative to the impact point, depending upon definitions. Applying Newton's Laws. It should be obvious that kinetic energy can only be transferred or transformed through force, because only force can change the motion of a mass. If the issue can be reduced to the question of what result force will produce, the answer is determined by Newton's laws. One of Newton's laws is that for every force there must be an equal and opposite force.
Forces can only be equal and opposite if they act for equal amounts of time.
And therefore, momentum must be conserved, because it is a product of Ft. When Newton's laws are applied to the situation described by Leibniz, and one theorizes the transfer of energy from one mass to the other while maintaining equal and opposite force on each, the Fs combination, or mv , is not conserved, while Ft, or mv, is. Later, a rocket will be used to produce the force. This amount of Ft stops the motion of m 1 . In other words, a 4kg mass dropped from 1 meter would produce the same result as a 1kg mass dropped from 16 meters, when the result is determined through equal and opposite forces on each.